I recommend you take a good look at the W-8, which is Sim's Evolution top model. It is H-E-A-V-Y. The transformers are HUGE. Basically, I'll parallel what someone else already said, that they will drive any speaker, and they have a 10 year warranty to top it off. I have compared it to the Classe 2200, and the Sim wins, easily. It has a tighter, deeper bottom end, and a huge soundstage. It also focuses better, and the top end is more detailed fast and extended. It is NOT aggressive, but very revealing. BTW, Ultra Audio, which is part of Soundstage magazine, just reviewed Sim's top three pieces, the W-8, P-8 and Andromeda, and were very enthusiastic, saying they even beat the mega-dollar Boulders in many respects. Plus, my experience with Classe dealers lately is that they seem to get very pushy, and I feel they are biased. It seems to me that Classe is only demo'd with B&W, and this seems obvious when you realize that they are both sold by the same importer. I cannot deal with a biased dealer, because I naturally feel they are not looking out for my best interests. My Simaudio dealer seems much more up front and honest. Now this may not be true for you, but I wouldn't be surprised if the Classe dealer you talk to plays you Classe with B&W. This is not because the match is excellent (although it is a good match IMO) but because they are financially bound to do so and contractually required by the importer. How can you trust a dealer like that?