That's interesting. I thought the same that the cubes were essentially the same just a bit bigger. I tried out the 30X yesterday, thought it was pretty good, quite warm. They didn't have a 20x to try.
I also tried the Marshall MG15 (I think), didn't really like the sound. Also tried a Fender Vibro Champ, very loud, good sound but I didn't like allthe voicings and effects, a bit to much for me.
I was recommended the Orange Crush 30R, by another guy in the shop. Has anyone had any experience with these, they seem to get good reviews.
My quest continues. :)