First: for me, these run a little large. I am a 6.5 narrow, and I had to return these for a 6.0. Even the 6.0 is a bit roomy, but with thick socks it's fine.

These boots are amazing! I really ask a lot from this type of boot. I live in Maine, and have a large energetic  dog who must be walked a good distance every day, no matter what the weather. I've bought and discarded several pairs of boots before these, including some from LL Bean (whose service, sadly, is not what it used to be). These are incredibly light weight- which makes a big difference when you're slogging 5+ miles every day- and also very warm. I have hard-to-fit feet, with a high arch, narrow heel, and wide forefoot- and these are as comfortable as slippers but also very supportive. Though many boots claim to be waterproof, these actually are.

I like the pullup closure, and the ski-boot-like Velcro strap. I can think of nothing negative about these. There was no break-in period, either. I just put them on and they were instantly comfortable.

I should also say that I did purchase a pair of these 2 years ago (from LL Bean, hence the previous comment) and had to return them because they split at the seam after only a month of use. I was SO disappointed, because I loved them so much, and Bean wouldn't replace them because they no longer carried them. I immediately regretted returning them, because as it turned out I spent 2 years trying to find a new pair, and couldn't. Then I saw them here on Amazon, and it looked as though they'd been re-tooled, with more rubber added to reinforce the part that had split. Time will tell if they split again. But if they do, this time I will do whatever it takes to hold onto them. I'll Superglue them, even Duct tape them, but I will never be without these boots again! In fact, I think I'll buy a second pair!