I'll say upfront that I have not owned PSA BHK power amps, but I do have experience with the BHK Preamp, which is lovely sounding. I have a great deal of respect for the late Bascom King and his designs. I do have a pair of AHB2 monoblocks on my 2 channel system and also use AHB2 on my headphone rig with Susvaras, which are difficult to drive.
I find the AHB2 to be straight down the middle. Not clinical and bright and not smooth and warm. It seems to be the closest thing to the proverbial "wire with gain", and in mono it has gobs of gain. For me, this is perfect.
In my youth, I worked in analog multitrack studios, 8, 16, & 24. Since then I've gravitated towards finding a neutral baseline, or at least as near as possible given the variability in playback systems. My goal has been to get close to hearing what's there on the recording. Not accuracy with respect to the live performance (which once laid down, is out of our hands), just accuracy in the recording's presentation.
The reason I bring all that up is I find the AHB2 to be a good baseline, neutral element in the chain. Of course, not all recordings shine in this neutral space. But surprisingly, I find the majority do. For those recordings that need a little help, or to suit my mood, I prefer to apply sweetening at the pre-amplification level; tubes for harmonic richness, modest eq., etc..
Just offering a perspective. Everyone's needs and situations are different and I'm respectful of that.