I think it is important to think about the speakers you want to use in deciding upon an amp - perhaps a dealer can configure a complete system. My experience with 300B SE amps is that they image well but lack power to handle some dynamics such as the cannon bursts on the 1812 Overture when use with speakers rated at 90db. I have had better luck with amps in the 35-70 amp range utilizing KT88's or KT90's. I would also suggest that you get an amp that has the option for triode or ultra-linear mode such as the Rogue Model 88 amp.
Advice from tube "lovers"...
...this is kind of continuation from my earlier post SS/ESL vs Tube/dynamic...i expected more of the "input"...but what i "gather" from few responses is definitely: TUBE! But which design and with what kind of tube you have had, best results? SE with KT88, El36, 300B or...? Or PP with KT88, EL36...etc! I know question does cover a lot, but ANY suggestion will be greatly appreciated!