Valet Pro seems to be popular on Detailing World. I use Auto Finesse Avalanche which is fairly good, but not as thick as others. I like that though, as to be honest, I don't really rate the snow foam process and think its a bit over rated. With Avalanche being the consistency it is, it doesn't dwell too long, so really just use this as a pre-wash, which suits my needs fine.
Here's some of a recent clean I gave the Wife's mini (power wash, avalanche for 5 min, power wash).
Before (4 weeks worth of country road driving):
During (shows the runny consistency as this was only after a minute of so)
After:
Megs hyperwash is another one that seems to get decent enough reviews, even though it's not actually a dedicated snow foam.
Head over to Detailing World - heaps of threads and opinons over there!!