I was worried about their sizing reading all of the horror stories. Their charts are spot on. I'm 6'2" 220lbs. I'm between a 34 and a 36 depending on how they're made. My thighs are muscular and I have a hard time finding pants to fit without them being too tight.
I bought some of their sierra pants in 36 and they fit perfectly. Probably some of my favorite that i own. Honestly, they're a bit more generous than the sitka mountain pants I have. I've gone on to buy a few pairs of attacks now too and they fit the same. Some are older (used) and they fit the same.
Talking with customer support, some of their pants are more of a tighter fit than others so maybe that's it?