I've never put tubes behind them, though. Based on their sensitivity rating, I see absolutely no problem in doing so. I don't know anyone local with a tube amp so I can give you a better opinion. Schuster has all solid-state (Mcintosh), doesn't he? I know Damon uses solid state as well.
For a used price in the $600s on Audiogon, I find it hard to think you could go wrong with these. They're the best monitor/bookshelf I've heard, but also give the Paradigm Studio 40 a listen - different ears and all.