I can't find any area where these 211 amps don't surpass the Krons. The thing that is unique in my experience is the sense of "integration" of the sound of instruments, voices, whatever. By integration I mean that all the components of the timbre of instruments and voices are now a single unit. It's difficult to describe and I'm probably not doing a good job, but this coherency of the music is just more focused, to a degree that I hadn't heard previously.
The resolution of timing is at a higher level, both micro and macro. For example, at the macro level, in orchestral works I hear more easily when an individual or different parts of the orchestra are a tad early or late. That must drive conductors crazy. I've just never been able to resolve these macro timing differences to this level before in recordings. It gives new appreciation for a really great orchestra and a disciplined conductor.
Yes, these amps are a new generation (#6 I think). Since I have only heard the amps using the KR-Labs 211, I can't speak to comparisons with other brands. Regarding biasing, the only thing I was told was that Lukasz suggests a bias range of 60 to 70.
Best,
Robert