I had the oportunuty to demo the Pathos classic one MK2, and personally didn't like what it did with my TSM-MX. Thin, and bright, is how I would describe the sound at times. I was kind of disapointed because I had heard the Pathos on a pair of De Capos speakers, and they made great music together.
The Stingray in my opinion is a great choice, I had them for a while on the Merlins and it was very nice, involving, warm, and enough juice for the TSM. The Stingrays are being shipped now, with a triode/tetrode switch, which I think is a nice addition.
Good luck
David