I get wonderful results with my Arye Acoustics MX-R mono blocks.
Other amps that I tried along the way to here are;
Bryston 7B SST mono blocks - good for rock and roll but lacked the finesse I sought
Musical Fidelity M7-700's - Jesus , these things were something like 1400w @4ohm. Only amps I ever tried that had enough power to make my MB2's squeak. Nice pair and well priced. Had the demo with the matching pre amp. Again great for rock , dance, hip hop and metal. John Lee Hooker was OMG good. But lacked the finesse I also craved
Audio Research Ref 150 - wonderful amp but not enough grunt. I did not try the Ref 250's as my bank account at the time would have collapsed under the weight.
Ayre Acoustics VX5 - Lovely bloody amp with the matching pre (KX5) but i wanted more power. That is how I ended up with the Ayre MX-R's, they do it all in spades. I ran the KX5/VX5 for a year or two until I found monos.
Note: After the MF mono block demo I got over bring home serious kit to trial, there were others I wanted to try. The MF bundle was 90kg for all 3 units and lugging that up and down 3 flights of stairs killed me
Hope this helps