Jeff, the M2 compares very favorably with the SET 300B. It's a beautiful sounding amp, and has a bit more control over the Tannoy woofers.
The SET beats it though, in musicality, and in getting closer to the sound of real music. Both amps are very satisfying to listen to, but there's something special about the SET, especially using the EML 300B XLS tubes.
When you visit Scott, maybe you and Scott could take time to drop by. (You too, Charles!)
Thanks and regards.