Reviewed by Gary123 from Washington DC area on Monday, February 13, 2012
I only just received these so I cannot comment yet on performance. But the pamphlet attached to the boot says the boot is manufactured with a 100% waterproof bladder. It says nothing about breathable and provides instructions on drying out the boot should the interior get wet from perspiration.
As to the size: I ordered two full sizes up because 1) reviewers recommended going a full size up, 2) I have a slightly wide foot and normally buy 1/2 to 1 full size larger for width, and 3) I plan to wear heavy wool socks with these. I am satisfied with the fit with heavy wool socks and the shoe with the heavy socks is a little over 1/2 too long. That's really fine.