Here are a couple of blog posts by a guy who tried the Altra Instinct (mens style). He lives in the PNW as well, and seems to really like them. He didn't mention slipping in them at all though he does stick to using his Merrell Trail Gloves for trail running.

http://welcome-to-briders-place.blog...sions-and.html

http://welcome-to-briders-place.blog...ail-glove.html

Oak - I'll be really curious to see what you have to say about them as the biggest shortcoming of my Evo's are the way the big toe space curves (instead of straight out like on my other Vivo Barefoot shoes).