Music Reference RM200 or David Berning ZH270?

Slowhand,
I have owned a Berning 270 and now own a Berning Siegfried amp. Since you have already committed to Berning, I would recommend several "tweaks" to enhance the listening experience.
1) Address microphonics. All Berning amps appear to be susceptable. I have used Halo's on the tubes and would recommend Symposium or Stillpoints underneath the amp.
2) A good power cord is a must. Try TG Audio or Shunyata.
3) Definitely tube roll. The Svetlana tubes are pretty good but you can sweeten the sound with some NOS tubes. Unfortunately you can't roll the output tubes.
I have found the combination of the above factors to have significantly improved the sound. Overall improvement in bass,less sibilance,sweeter midrange,increased clarity.
Enjoy listening.

Thanks guys, I have the TG Audio cord now and will check with Allan on the tweaks.

Be aware of 7-8 year old amps passing as new, there has been several changes since then.

The output tubes are very important as well, that is why I offer hand selected cryogenically treat outputs on mine.

Well guys, my deal on the ZH270 fell through. The seller misrepresented himself and the age of the amp he had for sale. The amp may be just fine for all I know, but I choose not to deal with someone who rates a product a 10/10 and I find out from Berning that it is 7 years old.

Slowhand, yea, wait for a good buyer - most berning owners are, but there are also some "proto-types" out there that guys seek to sell as better than the current version (and maybe but how do you know and resale is a killer...). People don't sell them much so you have to jump on them with a good seller immediately. Also, make sure you stick a good IC in their between the Supra and Berning. Put a Purist in there and some NOS tubes on the Berning and you'll be set for quite a while. let us know how it goes. Good luck.