Best Belay Device for Climbing Club

Our local university mountain club is looking to buy some new belay devices. Currently we have ATC-type tube devices for top-rope and single pitch leading, and guide mode devices for multipitch. One of the main things we're looking for in a new device is an assisted break, as we run trips with large groups of novices belaying each other on top rope.

The GriGri is the obvious choice from a safety perspective, but they're expensive and club gear has a tendency to go on walkabout/get dropped. Something that's a little more affordable for when we inevitably have to replace them would be nice. This has led to looking for a less expensive option, such as the Mammut Smart 2.0 or Climbing Technology Click Up, but we're in Australia and most of these devices aren't readily available for us to try out.

Could any of you with experience with other assisted-break devices provide advice on whether they'd be a good idea for our club?

there is a reason the gri gri has been the go-to assisted breaking device for the past 20 years. it has heritage, intuitive function, robust design and ease of use. you won't be disappointed.

The GriGri+ is pretty much designed for this.

I have the alpine up, the dual rope version of the click up.  It is a fantastic belay device behaves similarly to a grigri.  One thing i like about the alpine up over the grigri is that it has to be explicitly unlock after locking.  The grigri unlocks when the Climber unweights the rope.

Another big advantage of of the alpine up is that the rope can be taken in while the device is locked.  When i belay someone on toprope i just lock the device and pull the rope as the climber ascends.  In this mode  the belayer does not need to do anything when the climber falls, not even hold the rope.

Lead belaying requires the same care as always. 

If you can get your hands on it, the edelrid mega jul would be a good candidate. It's light, assisted braking, relatively cheap, and has a guide mode.

ATC Pilot is a great budget-friendly option that connects well to the classic tube-style.  

The free alternative is to ask your newer folks to have a backup belayer providing additional control of the brake strand during belaying with a manual braking device (ATC, Reverso, etc)

Intriguing question.  The Alpine Up, Mammut Smart, and Edelrid Megajul are all interesting ideas in that 1) they do offer brake assist, which could potentially prevent a novice belayer dropping a climber, and 2) they are all at least a little cheaper than a gri-gri or other mechanical brake-assist device.  

After using various ATC-style devices for decades, I have spent the last decade climbing mostly with an Alpine Smart or Megajul, and occasionally a gri-gri or Trango Vergo (my personal favorite of the mechanical brake-assist devices, though the gri-gri is far more similar than different).  I have also worked in outdoor education / institutional settings before.  If I were thinking about the needs of an institutional program, the things I might I like about the non-mechanical brake-assist devices would be

1) the assist is real and significant, if the brake-side rope is at all in the right position (i.e. not being held above the device somehow),
2) they are lightweight and have no moving parts (which also means they are threaded more like an ATC/plaquette-style device, which means one less threading technique to be taught),
3) they are perhaps the most versatile of all belay devices, offering brake-assist, double-rope rappelling, and a form of autoblock all in one (you could even ascend a rope on one in a pinch)
4) I could replace two of them for the price of one gri-gri, and
5) feeding slack quickly does not require a manual override of the device's braking ability, at least not to the extent of a gri-gri*

I think the downsides would be
1) they require a particular technique to feed slack quickly (this is true of the gri-gri and other mechanical devices as well, of course, but either way this requires integrating an additional habit into your belay technique,
2) they can be quite jerky for lowering and rappelling (this gets better with practice, but it is worst for heavier climbers)
3) they cause the rope to wear very quickly through aluminum carabiners (consider pairing them only with steel belay biners, or those nifty Edelrid belay biners with the steel inserts)

In addition to belaying errors (i.e. failing to hold a fall), consider lowering errors.  Gri-gris and related mechanical devices can be held open by their lowering handles.  If you get one of those style devices, consider the Gri Gri+, which has an "anti-panic" handle that will lock back up if it is pulled too far.  Meanwhile, the non-mechanical brake-assist devices are funny that way:  on the one hand, you sort of have to unlock them (i.e. push them away from your body by the "hook" part) to lower effectively, which could result in lowering too fast in short bursts, but on the other hand, the natural panic reaction is not to continue pushing the device away from you, so it is much harder for someone to accidentally hold the device "open" for very long if they panic while lowering.  Instead, they are more likely to pull their hands back towards themselves, which would encourage the device to lock back up.

If you do go with a mechanical brake-assist device, the Gri Gri+ is the dominant choice for good reason.  In their current design form, they are smooth and reliable and easy to use.  However, I personally like the Trango Vergo a lot more, for one big reason:  the technique to feed slack quickly without locking up the device is completely intuitive.  The way you hold the device is more natural and to me feels closer to my hand positions and movements when belaying with an ACT-style device.  To throw out slack, simply pull out rope sideways.  As soon as the device is oriented upward, it will naturally lock up.  The Vergo does not solve the potential lowering error problem, however.  I believe only the Gri Gri+ does that.

*what I mean is that to override the tendency of the rope to lock up on a non-mechanical brake-assist device, you don't have to put a thumb or finger on the moving part of the device and prevent it from locking up (in which case it is possible to tense up and keep the device "open" with your hand in the event of a sudden fall).  Instead, to unlock a non-mechanical device, you simply push the device away from you with your brake hand while it stays in position on the rope.  Therefore, in the event of a sudden fall, you would have to consciously push even harder away from you to prevent the rope from locking up.