Buy the OTB 500, change the 12AX7 valves to 12AT7's, and voila, more clean headroom.
The 500w version is loud enough for any size gig. Believe me!!!
For studio use, have a good DI box, with quite a bit of attenuation built in, as the signal from the DI is very hot as standard. The valve change lessens the hotness as well.
