I had some BD skins on my K2 Obsetheds. Just bought some longer skis and I plan on getting BD skins again. I've never used any other skins and I see no need to.
I have owned two pairs of g3 alpinists and they work pretty good. The guys I tour with use BD and seem to grip a little better and say they are more durable. I would get BD if you can, I only use g3 because I tour on Moments.