I've owned Densen B-350 Class A mono-amps, Classe Audio (Class AB), Parasound A21(Class AB), Peachtree Audio(Class D), Jeff Rowland M525(Class D) and have tried the Bryston 4bsst2 (Class AB). I currently own the Jeff Rowland Class D Continuum S2 and submit it's the most musical amp that I've owned. In addition, I love the fact that I can leave it on 24 hours a day and it doesn't get hot. I'm currently debating the Jeff Rowland 625 S2(Class AB), not because of my dissatisfaction with Class D, but my own stupidity. Unfortunately, I keep trying to go to the next level and incremental improvements are expensive!