I am currently running two Emotiva PA-1s in my stereo setup and in my opinion they are extremely neutral with ample clean power that will reveal what you feed them. Unfortunately I haven't used a Class AB amp in a while but coming from a Paradigm PW Amp, which was reviewed here, it's like night and day as the PW Amp, likely because of its noisy DSP, had lots of distortion.
I also run Dirac Live on my stereo setup which gives my small speakers a much fuller sound, with more clarity and a wider sound stage, likely because it is making up for the poor acoustics of my room and EQs the sound. So my takeaway from this is that the PA-1 is simply a clean and capable amp that will reveal what is fed into it.
I have ordered the Audiophonic PA-S125NC to drive my high frequency drivers in my active setup so I'll be getting my first taste of NCore, although the PA-S125NC provides much less power than the PA-1 but it will be interesting to see if I can notice a difference.