I've tried a bunch of high powered tube amps at the dealer, with Maggies, and witht he exception of the crazy priced VTL's and ARC's, they didn't hold a candle to the highpowered SS amps.
Bryston, SandersSound, Cary Mono's, Parasound Monos, those are the best that I have heard with Maggies.
You just need too much power for most tubes. Unless you bi-amp, and put the tubes on top. I am contemplating trying this again, but this time with Rogue mono's on top.