Didn’t use a 2:100 but did use for long time the 2:90 on the ULTRA and on the II.
It’s a great amp as long as you use ONLY this amp and not switching between other power amps as it colors the hell of the sound!
I switched lately to Matrix GT1000, less $$$, less weight, less maintenance (tubes ?) if any, less space in my rack, I'm much less concerned to take it out and be afraid it will be damaged and its not coloring the sound.
Above all my back is happy.
O and yes, I run a 4x12 and can even push 2 of this 4x12 without a problem.
BUT……in terms of brutal, I think the 2:90 was more brut, more aggressive in the sound, more like….hmmmm bad ? (in a good way of course).
But although that, I've decided to stay with the Matrix due to the mentioned.