There is no doubt that the Tenor/Midi Grand combo is much better sounding. That being said, Tenor is currently out of business and not producing the amplifiers right now. That being said, the designer and lead technician are fully supporting the amplifiers and are easily reachable in Montreal.
The OTL's have always been reliable as long as they are run with a speaker that has a benign impedence. No different than any OTL amplifier in this regard.