backpacking pack suggestion

I have a trip planned for the wind river range in august and need to purchase a larger backpack to carry climbing and camping equipment for a total of 5 days in the range +2 days of to and from travel (only checking one bag). I'll be splitting the load with one other person when I get to WY. So far I am between the, 4400 Porter or Windrider (like the mesh pocket) from Hyperlite, the Aether pro 70 from Osprey, or maybe one of the terraframe models from Mystery Ranch since they are expandable and could accommodate my multipitch pack nicely. Any clear reasons why I should go for one over the other? Should I be avoiding any of these as potential options?

No experience with any of the packs you mentioned. I got a Deuter 65+10 pack. Fully adjustable, light for what it is, and comfortable. Easily carried a bear canister packed with food, water, camping gear, climbing pack, helmet, and a single rack with double ropes. My wife has an osprey. By comparison it feels heavy and over designed...

Christian Schrader wrote:  Any clear reasons why I should go for one over the other? 

Fit. Try all 4 packs on in the store, get a competent person to help you adjust them to your body, and wear them around the store with enough weight in them to approximate the weight you'll be carrying on your trip, and pick the one that feels best when it's loaded and on your back. If you can fit all your stuff in it, and if the price is in your range, the Arc'teryx Bora AR 63 liter is worth trying on, if you haven't already. The Gregory Baltoro packs are worth trying on, too.

As said above, the Gregory Baltoro series is a comfortable load-hauler.

Camping for 5 days and taking climbing gear would leave me to recommend you look bigger than 70 liters. I don't think that'll do it. 

Hyperlite packs carry like a dream, i used to have a porter and always wanted the mesh pocket to throw stuff in, water bottles, etc. would make for a great cragging pack as well. You can gently bend the aluminum stays to adjust the fit. I have had their ice pack for 3+ years now. They can’t really be destroyed.

I’d say get the wind rider

I have a size large HMG southwest 3400 in black, only used a few times, if your looking interested 

I’d recommend you buy my Dana Designs Astralplane & spend a lot less money than on those other packs.

I have fairly extensive hands-on experience with all of those specific packs and own, and have subsequently used and abused, versions of all 3 (I own the HMG 3400 Southwest, Aether Pro 70, and MR Sawtooth, which is just a hunting version of the TerraFrame series). They're all excellent packs and you can't go wrong, quality wise, with any of them. However, first off, Mark is absolutely right with fit being the most important thing to consider. When hauling loads as heavy as these packs are designed for, a proper fit should be the first thing you consider. You'll be miserable if its not right and won't get a chance to enjoy the features of a pack that fits poorly. That being said, it is possible that they could all fit you, since they all fit me (~6', 170 lbs, 30-31" waist, 18ish" torso, relatively slim upper body, average width shoulders for a climber, mesomorph body-type). So from now on I'll be operating under the assumption that you either can't try them on for whatever reason (but seriously, try as hard as you can to do so, since they feel quite different from each-other), or that you have had the opportunity to do so, and find that they all fit you relatively well.

1. How much weight do you plan to be carrying, and how far in is the approach?  
   • If you're gonna be carrying 50+ lbs in and out, the TerraFrame and Aether Pro are gonna do a much better job transferring the load to your hips in an efficient manner due to frame/hipbelt construction and bag shape. 
   • The HMG certainly can carry those loads more comfortably than any other sub 2.5 pound pack, but while it is rated to 60lbs and won't be compromised at those loads, I'd put the comfort limit at 50 and below.
2. What sort of approach are you anticipating and what is your experience level with backpacking? 
   • Well maintained trail all the way to your camp at the base of the walls? Decently graded but rarely used trails with some off-trail navigation? Full-on 'shwacking through thick forest and underbrush the entire way? Above treeline, off-trail navigation on talus slopes? Doing any serious river crossings?
   • Are you comfortable packing and distributing weight properly in a big top-loading hole (HMG and Aether), or would you rather have more organization (as in the TF)?
3. What types of future trips do you intend to use this on? 
   • Is climbing your main outdoor pursuit and you're only using the pack as a means to get you to the walls, or do you backpack frequently without climbing gear as well? Are you into mountaineering? Packrafting interest you at all? Do you hunt? Do you like snowsports and getting out in cold weather? Do you do trail building/maintenance often?
4. What's your body type? 
   • Generally speaking, Osprey packs are designed to fit ectomorphic/mesomorphic body types best. This means that the yoke (shoulder harness) tends to be a bit narrower-set at the neck, and the angle of the shoulder straps are typically more ergonomic for someone with less broad shoulders and a less developed chest. Additionally, the padded portions of the hipbelts generally don't wrap around as far as a pack of the same size designed more for endomorphs. Built for those with narrower waists in the X and Z axis. The Aether Pro generally holds true to this formula, the yoke is just wide enough for my neck (I get some rubbing if its not adjusted just right), and the shoulder straps are right on the edge of comfort where they hit on my chest. However, the hipbelt extends a smidge farther than I've found most Osprey's do, and the heat-moldable aspect is nice since over time it will mold to your specific hip structure.
   • Generally speaking, MR packs are a better fit for mesomorphic/endomorphic body-types. Yoke is a little wider-set at the neck and the angle of the shoulder straps accommodates broader shoulders and a more developed chest. The hipbelt design is excellent and it seems to adapt to multiple body types quite well, though I think it does do a better job on the Endo side of the spectrum than on the Ecto side. My Sawtooth (and by extension the TerraFrame) tracks with all of those generalizations.
   • HMG's are the most lightly padded, least breathable, least supportive and most basic design, but the harness system fits most Ectos and Mesos well and punches well above it's weight.
5. Additional things to consider:
   • Mystery Ranch Terraframe 65 or 80 - BOMBER. 
     • Heaviest of the three (5.7-5.9 lbs) - Most abrasion and puncture resistant, can spray down with a pressure washer, burly zippers, buckles and webbing, I'd frankly be amazed if you can kill one. Slightly softer foam than the Aether Pro or HMG but it holds up really well over the long term.
     • Definitely carries the most weight of the three (rated to 150 lbs and I believe it, I've carried ~110 lbs for ~4.5 miles to a supply cache in my Sawtooth and it wasn't even phased, unlike myself who fully regretted the decision to make that hike.) The overload feature is clutch when you have to carry awkwardly shaped items long distances (water jugs, huge basecamping tents, packing out meat, pfd's, someone else's pack that broke, chainsaws/gas cans, tools, etc.) but the bulkier the overload in the Z direction (away from your back) the more the weight in the packbag will pull you backwards and there's not much you can do to combat that if you aren't able to compress the overload.
     • Does not come with hipbelt pockets, though you can purchase them in various sizes, along with a TON of other accessories that add a lot of functionality. Pack-lid doubles as a very respectable daypack.
     • Honestly, as much as I love mine and consider it irreplaceable for the situations I use it in, I bought it specifically for guiding/hunting/trail maintenance, and unless you anticipate needing to frequently carry large, awkwardly shaped items, I think that its probably more pack than you need. The Baltoro below has a similar fit in a more conventional design and has been tried and tested in load-hauling backpacking situations for over a decade.
   • Osprey Aether Pro 70 - A solid middle ground, weighs under 4 lbs but still able to carry up to 55ish lbs in relative comfort.
     • Compresses decently and can strip pack of all it's compression straps, top lid, and hip pockets if desired. I find all of the extra attachment options to be great for carrying tents, foam sleeping pads, snowshoes, and other bulky items to save space in the packbag for food, water, climbing gear, clothing, etc.
     • BV500 does not fit deep in the pack horizontally, though it will fit under the lid/in the shroud horizontally
     • My pack of choice for long backpacking trips where I need more than just backpacking gear and/or have no opportunity to resupply.  Is a good balance of being relatively easy to pack, carrying oversized/heavy loads well, and being lightweight and durable.
   • HMG 4400 Porter or Windrider - The lightest weight (>2.5 lbs) most water resistant and most compressible option.
     • Excellent abrasion resistance, puncture resistance leaves a bit to be desired over the long-term (pinholes tend to occur as HMG's get older, but they don't compromise the integrity of the pack in any way, apart from having to be a little more carful about water penetration)
     • The plastic framesheet on the 4400 sizes does a better job protecting your back from pokey objects in bag, but you'll still need to take more care when packing your cams than you would in the Osprey or MR. 
     • BV500 will fit deep in the pack horizontally, though it does tend to cause pressure points so I prefer to carry it on top with the Y-strap if possible. 
     • If you're near the top of the size range, size up.
     • Even if you are already an experienced backpacker, this style pack at this size is the most challenging to pack properly, and you will suffer the most if it isn't packed well.
     • I'd take the Porter over the Windrider personally, though I'm interested to hear why you like the mesh pockets.

 Additional packs/things to consider: 

• As noted upthread, the Gregory Baltoro is an excellent load hauler that can carry 60ish pounds with the best of them, if it fits you properly. It offers more lumbar support and a fit that is generally more conducive for those with broader shoulders and/or upper body in general (can switch out hip belts for smaller sizes) - Endomorph body types generally fit well in the Baltoro, whereas Osprey packs generally fit ectomorphs a little better. MR is in between but generally fits closer to the Baltoro.
• The Sierra Designs Flex Capacitor 60-75 is another interesting option at 2lbs 10oz and $220, it's significantly less expensive than any of your other options, but the unique frame system allows it to carry 50ish pounds relatively comfortably and expand or contract based on your load. All while being almost as light as the HMG! Downside is durability from an abrasion resistance standpoint if you're gonna be dragging it past rock or doing a lot of bushwacking, as well as not having much in the way of pocketry or organization on the outside. Also the fit can be polarizing, but if its right, its a heck of a pack for steal of a price.
• Unless you can get a killer deal on it, the Arc Bora probably isn't worth it for you, even though that pack is seriously cool. The capacity likely won't be enough for this trip, and you don't need to spend $550 on a pack, unless you already know you need to spend $550 on that pack in particular. I.e. If you don't know you have a problem that only the Bora can solve, you don't need it.
• Someone else upthread mentioned a Deuter. I've found that the larger Deuter packs don't fit most people as well as either an Osprey or a Gregory does (as far as mass-market pack manufacturers go), but if nothing else fits your body shape, the Deuter AirContact Pro 70+15 might be one to look into. Heavy AF though at 6.5 lbs.

*Disclaimer* - I outfit for a living, gear-whore and research like it's my job, and have been a backcountry guide for several years, Apologies for the torrent of information, but if you want to talk more about packs, I'm more than happy to answer questions/clarify.

Ben M wrote: I have fairly extensive hands-on experience [...]

Thanks for providing such a thorough and helpful response Ben. 

Sounds like a plan, I think the Aether Pro and Baltoro 75 are likely the best match for you as well and it should come down to fit between those two. Let me know how it works out!