I think "the best" is a question too system dependent to answer without equivocation. You'll find proponents of Bel Canto & PS Audio, each singing their praises. The PS has been a revalation in my system, very good synergy with my Magneplanars. The question about preamp matching is very relevant in my experience with this amp. I am using a Music Reference RM5III that has variable gain. The systems' transparency, lack of grain, etc. is much better at the very lowest amount of gain possible, which is 3.5 db. Higher amounts of gain degrade things very noticeably. The input sensitivity of the HCA-2 is higher than average. However, the factory is happy to build an amp for you with lower sensitivity suitable for a given preamp with higher gain. If you are fond of passive preamps, this is a great amp for that route. Remember, if you order from the PS Audio factory, you get a trial period.