Sherpa Benet wrote a review of Arc'teryx Perimeter Pant - Men's on December 12, 2013
Familiarity: I've put it through the wringer
Fit: Runs small
These have pretty much replaced my Ramparts and even older Candidate pants from Arc'Teryx. These are a great material; they are softer, smoother, and stretchier than the Ramparts and shed water better. They pack down small and don't hold a wrinkle.
I don't know how so many reviewers are saying these shrink; they're a nylon/poly blend of fabric. I've washed and dried mine dozens of times over the past 6 months and they stay the same size & length. Having said that, they are like nearly all of the Arc'Teryx hiking/climbing pants, which is to say that they seem to run about 1/2 to 3/4" short in length. This is great to keep them out of the way for outdoor pursuits, but they do tend to look a bit 'high-water' for urban adventures. For the sleek look and comfort, though, I don't mind terribly, but if they were available in a 33" length I'd choose those.
These are also an 'athletic fit', meaning they're pretty slim. I have an 'endurance' build and these don't leave me a lot of room. They're not tight, but if I were to miss a couple weeks of training they could get that way. Definitely not made for guys who spend their gym hours at the squat rack.
Only other place I'd look for improvement is to have cargo pockets on both thighs, and maybe add a zipper or 'credential flap' to the rear pockets, and a hidden zip to one of the hand pockets to keep gear secure.
If these came in olive or coyote/crocodile I'd buy them again without hesitation.