I tried a few Babolat "soft" grips -- but they were just too soft and too puffy.
The closest thing to Wilson air sponge I've seen was the Kirschbaum grip. Kirschbaum is just a tad softer, and has a smooth uniform surface, which I like. I rank both the Wilson AirSponge and Kirschbaum as "medium soft". They are just the right softness for me.