I've owned Lamm M1.1's and M2.1 and my friends fell in love with them but then I heard the VTL S400 releasized I needed some more clarity and also surpising the VTL went lower and deeper and it was definitely tighter.. I can't imagine the Belles comparing to the Lamm's as they are really addictive and some day I'm dying to get a set of Lamm ML2.1... If you run the Lamms in a home theater setup you better drop the center channel because there is no way you will find a matching tonal center channel amp... run Phantom Mode..
Sutts: The Lamm M1.1 versus M1.2 ..yes the M1.2's are better (not in a huge difference as he just used more currently available parts) and they provide like another 10 watts a channel. The biggest advantage are they are newer (since these run in Class A full time) Expect to see them listed for about $6000-7500 for Lamm M1.1's and somewhere north of 10k for M1.2's. Oh yeah and buy the 6922 input tubes from Lamm as they were like $25 each from them.... total no brainer bargain..
As far as the VTL amps.. 6550 tubes from VTL are about $60 each but you can get between 5,000-10,000 hours I out of tube the way VTL runs them... plus the best part is no matched pairs,quads, octets.... so way cheaper than ARC retubing... one tube blows, just drop in another. The new VTL450 signature has the computer controlled biasing which is awesome... similar tech to the S400 stereo amp. VTL no problem for home theater...
As far as Music Reference amps... I have owned the RM200 twice and I still regret selling it.. it's not as organic/seductive as the Lamms but it's more open on the top and crystal clear with even 2ohm control.. it only requires a Quad of 6550, or KT88's tubes which I recommend buying from Ram Tubes (Music Reference's company) especially the input tubes because they DC stress them which no one else does .. Music Reference amps aren't hard on tubes and tube that would be noisy in other amps are quiet in the RM amps.. The older RM9 required more expensive Matched Quads to achieve 100watts a channel or 125watt a channel in the RM9 MkII. These don't have the iron fist control of the RM200 (which can borerline on sounding similar to the high end SS Ayre amp in clarity and control) This might be similar to the Vac with the sparkle, and also without the constant repairs my friends have had with their VAC's (they sold them now and went back to solid state... after 3 roundtrips back to the factory..) Music Reference.. no problem for home theater.. Check out Audiocircle dot com for the Music Reference Forum, I'm sure you can post and find someone near you to hear these amps.. very minimalist but bulletproof design and they sound great!