I've been using a pair of the Quest 4D 3 GTX's since last summer for hiking and hunting. Mine have been working pretty well. I wear size 11 Nike, and size 11 fit well. Probably the most comfortable boot I've had in a long time. Did some backpacking in Colorado and man, they have some grip on rocky surfaces! Mine have held up to frost, wet snow, and puddles well without leaking. I am a little anxious to see how they work in the spring dew. They seem a little soft for busting through upland cover and have some scuffs here and there from pheasant hunting, but nothing horrible. I am a little worried about durability due to the large amount of seems they have, but so far they are holding up well.
I read quite a few reviews prior to getting mine and it seemed like they either leaked or they didn't from the get-go. Most of those were from the previous model through. From what I've read I'd recommend testing them out after you get them so you can return them if they leak.