I'm in absolute heaven with the Kanta No2's.
I'm running a solid state amp and hybrid pre (BAT VK-220 & BAT VK-3iX). I wouldn't hesitate to use all solid state as long as it's got current and decent specs. They're far more efficient than I had anticipated. The Stereophile review used 2 class D monoblocks.
As far as bass, the 2's have serious grunt power. I seriously don't know what people listen to these days, but assume the need for so much bass comes from Transformer movies? I wouldn't want to pair these with subs at all, but in my case they're strictly for music/2-channel.
My listening "area" is approx 18x19 with a 20' ceiling. It opens onto a kitchen, staircase, catwalk and foyer, so it's really quite a bit larger. The floors are hardwood over slab. I'm not settled on the final positioning layout, but I'm really glad that I didn't set up in my living room, which while more contained and easier to tame would have been far too small.
Perhaps Steve59's issue was the Kanta 3's weren't broken in. I've heard plenty of complaints about thin, lightweight and harsh until they've had a few hundred hours (again, see the Stereophile review). Mine had already spent considerable time playing before I got them.