Easy...Uberschall. 101b can do a lot well but it's looser in the low end and has a smooth midrange/high end. It's a greasy rock machine, the Uber is sort of a Recto with a bit more of a Marshall crunch. Nice swirl to drop tuned power chords, spongy dark-ish tone...elastic feel, not as immediate as some...can sound a bit bloated till it opens up and purrs...Twin Jet is tighter and has a more Marshall like crunch channel with big lows.