I went up to Denmark Street a month or so ago and had the chance to try, one, two and three. I' not a tech freak so this is just the gut response as player. The original question in my mind the time was should I buy used bass cube II? I compared the face value usability of the Cube and in very case amps one, two and three spanked it for me. The sheer power and depth each one had over the albeit very sophisticated Cube made the decision easier - amps1-3 Bass Guitar - Bass Cube Double Bass. So I then compared amps 1-3. I had fixed cube gas.
One was amazing, tiny, impossibly clear and loud, you just sit and scratch our head - WTF was my only thought. The tone was pretty much all there but I felt as if AER had tried to make the smallest possible serious combo and succeeded! BUT Then looked at something to compete with the Mesa combos- the Two does that. It felt more like a 'real' useable gigging combo. Loud, bright (perhaps to bright) and punchy as hell. for me the One just didn't answer all the questions, the two answered all of them but it is bigger, heavier and if I wanted - a compact combo to sling on the passenger seat? Two was not it. So Thee .............. 2x 8" a little bigger than One but still tiny.
Take all the other small combo's in the world and build a big bonfire........... Three is awesome.The bottom end is mind bending and can only be heard to be believed. It is punchier than One, it is warmer than One or Two and GDAM that low end. This is the tiny combo you can trust with your low B, or with the warmth of a vintage P bass in my view. Mine is on order for Xmas, you gotta try it.