The fit is comfortable and wears like a ski boot. Plenty of ankle support.  The upper and top of the boot keep those areas warm.  There was a tag that came with the boot saying it was rated to -25F.  I have a pair of 511 hiking boots that I use in the summer because that is what they are designed for.  The 511 boot keeps the bottom of my feet warmer than these winter boots.  I have worn these Bugaboot Plus for a few weeks now in temperatures ranging from -15 to +40F, in snow, slush, rain, and mud.  The bottom of my feet get cold within 20 minutes of my hike.  I wear Wolverine wool socks mostly, I have tried other combinations but the same thing happens the bottom of my feet get cold.  The terrain I walk on includes asphalt, rock, mud, sidewalks, and through brush.

I will keep them, but if I plan on being longer than a few hours on the trail I will be looking for another pair of boots.