Smholl, I think you posted the same question in audioasylum, so I'll repeat my response here:
I auditioned my friend's SX-500s in my system. I loved them so much I got ready to order them. I was recommended the the mAMPs instead. The mAMPs are supposed to be based on the latest ICE modules and use a newly redesigned input stage, with noticeable improvements; thats why I went with them instead of the SX-500s. Given my relatively efficient speakers in a small room I did not need the power of SX-1000s. I have not had a chance to do a direct A/B comparison between the SX-500 and mAMPs, but I suspect the mAMPs may have the edge.
I've had the Wyred 4 Sound DAC-2 running direct into a pair of mAMPs in my system for over a month now and they sound fantastic. A significant upgrade over a Cullen modded PS Audio chain: DL3 --> Trio C-100 they replaced. Dynamics (macro and micro), details, bass performance, etc. have improved significantly.