Three months ago, a day after my first climb, I bought a pair of Defy shoes with the intention of dedicating the summer to learning how to climb. In pursuit of this goal, my Defy's spent at least 2 hrs, 4x/week, on my feet either in the gym or at the crag being critical to my progress through 5.10d lead and V3. I would recommend these shoes to others with the instruction to keep a few things in mind before they buy.
1) They do stretch. I wear 10.5/11 in street shoes and got them in 10.5. After suffering for a month, they finally broke in and became quite comfortable. In the middle of month 2, however, they had stretched too much, and as I was getting better and needing to dial it down, the velcro straps wouldn't go far enough to allow it. My next Evolv's will def be a size or more down. The break-in time will suck, but I'll end up with shoes that fit so well, I'll be very happy to pay for resoling.
2) The rubber runs out pretty quickly. I've heard others talk smack about Trax rubber, but I've found it quite sticky and trustworthy on sketchy clips. The problem is that I have two gaping wholes in the toes, and the rubber on the heel is separating from the shoe. This may be due to beginner's footwork, but other reviewers have mentioned the same problem.
3) Lastly, I know it's weird, but they really do reek! I was happily surprised to read this comment in other reviews (glad to know it's not just me). So, make sure you get odor eaters, or something.