2 channel Sunfire amps.

Does anyone have any info on the best Sunfire stereo amp. I've seen that there is a Signature 600 and a Mark 2 version. What are the differences between these models and how does the sound quality and prices compare. I have been looking at McIntosh amps to pair with my Sunfire vacuum tube preamp but some Audiogoners have commented that the Mac amp would totally outclass the Sunfire. Also what would be a good speaker for the Sunfire combo? Any info would be greatly appreciated. -Don