Marsh Amps

How good is the Marsh 200 watt amp? As good or better than the McCormack DNA225? How about the Plinius int.? I own B&W speakers. Thanks.

I can answer the question "How good is the Marsh 200 amp?" but cannot compare with the McCormack or Plinius as I have not heard either.

Along with the Marsh 200, I own Sony SCD 777, Placette Passive linestage and Harbeth Compact 7 ES Speakers.

The Marsh 200 is a great sounding amp. Previously, I had a CJ Premier 11a and MV55, and I can honestly say the Marsh does not give up anything in the midrange to these two tube amps that are famous for their midrange, and betters them both in frequency extension, bass cleanliness, transparency and detail.

The Marsh is an exceptionally good deal, in my opinion. It is hard to believe what $800 (approximate used price)can buy these days.
The Marsh A200s is 120wpc, the 200wpc Marsh is the A400s and has been listed for as little as $1400. Both are a steal on the used market. I have compared my A200s to some very nice stuff and it really holds its own. It sounds powerful and has a very open high end. Marsh amps are for real.
I previously owned the DNA225, and once auditioned the Marsh A400 in home next to it. My speakers are Magnepan 3.6/R, which are quite revealing, and I found these amps a bit too forward and bright in the upper mids/treble in my system. However, they both present very clean sound, and might do quite well with warmer and/or dynamic speakers. To me the DNA225 is slightly more refined in the mid and upper ranges. (Warning: Adequate break-in is critical with both these amps before full evaluation.) In terms of bass, the A400 seems tighter overall, while the DNA225 delivers a bit more bass energy even if it's less defined than in the A400. Finally, the DNA has only RCA inputs, if that matters to you.
I'm currently driving some dynamic speakers with a McCormack DNA-0.5 Rev. A and will soon be plugging the Marsh amp into my system for comparison. I'll let you know what I find. A lot of B&W owners seem to really like Classe amps for what it's worth, so they also may be worth a try.