@jamesh Because of the difference in price points, I would expect a lot more than just a big step up .
I’m currently using a NAD M22v2 power amp. It drives my Tannoy’s with ease and the SQ is quite good. I suspect the M700s would sound better with the BHK preamp and I’m convinced the BHK 250 would sound even better; somewhere between the two lies the M1200’s SQ. I’m also looking to move from a Furman power conditioner to a Power Regenerator and, from what I understand, that decision depends primarily on the power amp. That leaves me with two logical choices - the P12 (M700 or M1200?) or P15 (BHK 250).
I will say that I have been satisfied with every PS Audio product that I’ve purchased to date. I’m considering the cost of everything against the overall improvement in SQ, and since I can no longer audition PS Audio gear locally, I’m having a hard time making up my mind on which power amp to buy. Your home trial, and trade-in and customer loyalty discounts are great. I will certainly take advantage of them once I decide.