I would agree that a powerful amp goes a long way with these. Not a requirement by any means, but very helpful IMHO.
I have owned a pair since shortly after they were released (about 2 years now) and have run them with Simaudio W6 monos, Bryston 4B-SST, and a pair of 7B-SST. The 4B couldn't quite cut it (timing, resolution, were not quite up to par compared to the monos). But upgrading to the 7B's made all the difference. The W-6's also sounded killer but not quite as neutral as the 7B's, it would come down to preference in that case. I'm currently using the 7B's. Good luck.
I have owned a pair since shortly after they were released (about 2 years now) and have run them with Simaudio W6 monos, Bryston 4B-SST, and a pair of 7B-SST. The 4B couldn't quite cut it (timing, resolution, were not quite up to par compared to the monos). But upgrading to the 7B's made all the difference. The W-6's also sounded killer but not quite as neutral as the 7B's, it would come down to preference in that case. I'm currently using the 7B's. Good luck.