I have the standard Flex version. I am 6-1 and 195lbs. US Medium fits me like a glove. They work well under a harness. Otherwise the pants look like you are wearing Gucci to the crag...lol. Zippers are the smoothest I have encountered. They climb great with no restrictions (even tightly fit) and you can get a lot in the pockets
The only gripe that I have is because of the side zippered vents in the sides of the thigh. Because of this the thigh pocket and to be forced to close to the front, so your phone tends to scrape more in wide cracks. I have the shorts which do but have this issue. I highly recommend the shorts.