Several years ago, I opted for the RM-200 after listening to almost two dozen amps of various types (tube, transistor, hybrid) and a wide range of prices. My search was inspired by my purchase of a pair of Wilson WP7 speakers that sounded wonderful with my Spectral DMA100 amplifier but not as organically musical as when I had heard them elsewhere. My choice was guided by my wide ranging musical tastes, occasional desire to play at loud volumes, and that the system would be playing in a space of relatively modest dimensions (~2,200 cu. ft.). To make a long story short, I selected the RM-200 because it was best at getting vocal and instrumental timbres correct, outstanding at presenting the dynamic envelope of recordings without compression or strain, and that it had the best combination of bass extension and tone. I was also enthusiastic about the excellent reputation of MR gear for reliability and tube life that Pubul57 mentioned and which has been well borne out during my five years of ownership.
I would, however, recommend that you listen to a few amps that I thought were better than the RM-200 in one or a few ways, but were not as ideal overall for my taste. The Jadis Defy 7, a 100 wpc tube amp (Mk. IV, I think) had a way with female vocals that was peerless and rendered violin and viola string tone with an almost technicolor intensity. Dynamically, though, I was not as delighted because it seemed to present percussion instruments with a consistently more distant perspective and softened focus. The BAT VK-600,
a 300 wpc transistor amp, had the best bass extension and impact of any amp I auditioned. By comparison it made the RM-200 sound a bit thumpy. However, I found the pitch definition of electric and acoustic basses at the lower ends of their ranges to be better with the RM-200, so runs up and down the fretboard were more timbrally consistent and convincing. The huge Audio Research Reference 300s, 300 wpc tube amps were supremely clear and present, presenting images and soundstages with absolute precision and continuity. They were also spot on dynamically, every note having proper speed and duration, yielding percussion instruments with all of their thrust and pop intact. Initially, I was totally bowled over by these but after the second audition found them to be lacking in timbral completeness over a large range of voices and instruments.
The most important lesson that I learned from this exercise was that you have to be patient and have your musical priorities well sorted out. Nothing can substitute for the exercising of your critical faculties during the selection process. It also helps a lot if you use the same brand and model of speaker for your comparisons, and that you are at least somewhat familiar with them. I also think that it helps a lot to have the assistance of good audio professionals. They can do a lot to help you identify your musical priorities and maximize the likelihood that you will get something that fits. They can also make the process a lot more fun.
I wish you the best of luck.