Which Class D Amplifier? PS Audio, Ghent, Nord, Merrill or other???

+1 Nuforce/Nuprime, particularly with Bob Smith's TDDS factory authorized mods. I had their monobloc Reference 9V3Se, then Reference 20 and Now Evolution One. Have heard many other class D and these are best I have heard. Disclosure, my Reference 20's are up for sale here, but with sale pending. They also use an original design versus standard or modified chips

NAD doesn’t get a lot of love on agon, but you might want to look at the NAD M22 v2.  Paired with the NAD M12 pre/DAC with BluOS module, they drive my Tannoy 8 dcti speakers quite well.

 I like Stevecham am enjoying my M700's .They can't be beat for the price. Collectively, a system costs are considerable so when you can get great performance and save a few to put into other areas in your rack you can get better balance. Steve, I would highly recommend getting a Furutech IEC and AMR fuses for the M700's. Those 2 tweeks made a considerable difference. The AMR fuses are awesome. I preferred them to all the others I've tried including all Synergistic fuses. Trust me.

+1 to Nord
I have the Nord One UP NC500DM stereo amp and it outperfoms in EVERY field my previously beloved 300B valve integrated (use as a power amp) Line Magnetic LM-508IA, wich is a very nice class A valve amp, very popular among audiophiles and cost almost 3 times the Nord. 
Besides that, if you are in UK, may be you can visit Colin to test his products.

Avoid Class D like monkey plague!