Difference between Sonic Frontiers SFS and power

The SFS and (SFM mono amps), tend to be a bit warmer in comparison to the Power series. Build quality is arguably a bit better in the Power series, but both are built like tanks. Sonically the Power Series are more like "liquid SS amps". The sonic signature of the SFS series is different in each model. The SFS 40 is warmer than the SFS 80, which is warmer than the SFM 160s (the number designations approximate the wattage). From my limited experience with the power series the tonal signature of the power series is somewhat cooler, and for me a tad too cool. Although if you like that, the Power 2 is a great buy (I see them going for about 2K).

How does this compare with Counterpoint SA series amps?

My unreliable aural memory of the Counterpoint Amps and pre-amps is that they were voiced on the cool side, probably closer to the Power series (the key word is probably) I've never done a comparison. Counterpoint point stuff has a bit of a reputation for unreliability which is not a problem with the SF stuff. Do some research if you find yourself attracted to the Counterpoint.