I've worn the non-GTX version, but due to my work lotation change I needed GTX version. Not to my surprise, these run very very small. In fact, I would recommned ordering a size or even a size and half up depends on type of insole and socks you plan to wear.

I also notived, GTX is stiffer than non-GTX, perhaps due to waterproof liners.

More review to follow if I decide to keep them.

==update==
Unfortunately, these boots have zero traction on snow. With recent snow storm I wore them to remove snow and get my car unstuck. Well, these boots aren't meant for winter or snow.

I still like them for desert sand, mud, and indoor. Just be aware of the snow traction.