In reply to galpinos:
A friend (Danny, we were in Norway with him) has the Trango Cubes and really doesn't recommend them. I can't comment on the other two you've mentioned.
I use LS Trango S Evos for summer alps and they are the mutts nuts - light, comfy, waterproof, pretty good for climbing in (when I did the Cassin a few years back the couple behind us were climbing in them!), B2 ... plenty of deals on them at the moment too.
I'll probably be out in the Alps for some of the summer, so give me a shout if you want to meet up!