"Better" or "Best" is what I try to avoid. Why not call VTL and see what they might be able to share on the pros/cons of the S vs. MB models, in a general manner, but also for your speakers. I have the the Amati Futura and these need serious current drive to get the woofers to come alive. Sadly many well-reviewed "high-power" amps, SS and tube, choke with these speakers. If you seek a tube amp, you should also consider the Manley amps AND CAT.