I think they do a lot of things very well. Good resolution without being hyper revealing, nice tonal balance, soundstage is wall to wall, the dynamics and impact are exciting, and they seem to do well with both tubes and solid state. I'm still dialing them into my system. I find them sensitive to different things than I am accustomed to, such as noise floor, gain, and things that influence timing. Regarding the output impedance of my tube amp, I don't think I'm getting the same power as before with the output fixed at 4 ohms. Still enough to comfortably cruise at 100 spl if I want to, but not with the same punch. I have some modest 200 watt Outlaw monoblocks on hand that were only average sounding with my last speakers that kick butt with the 7Pi. It seems to me you can get good results without going overboard on amplification with the 7Pi.