I have some Defrosters – technically ‘waterproof’, practically ‘water resistant’, dry slowly thanks to the membrane, grip is slippy on rock, just about adequate on softer ground, sole lugs tear off with heavy use. Not warm, I kind of view them as a lightweight wet weather option rather than a ‘proper’ winter boot.
Have a pair of the Shimano hiking-style boots with the Gore-Tex liner and leather uppers plus Vibram sole, which I use for sub-zero stuff with a mini-gaiter and thick wool socks, which I really like – good for pushing through snow too.
Also looking at the new Mavic Scree, which I’m told is due in the shops in a couple of weeks time. Gore-Tex liner, the Mavic sole unit which is ace – look like a better alternative to the Defroster, though may need some sort of mini ankle gaiter to improve sealing.