Quoting me... They prefer higher impedance speakers. I remember there was a fellow in NY who had the Soundlab driven by Atmasphere and I really liked the sound.. Then, its Soundlab had a nominal impedance of 16 ohms Beautiful sound.Some brands/designs company have attained extremely good reliability with OTL among them Atmasphere and Joule Electa
As for the heat ..I had forgotten about that part of the OTL equation... he had a special vent over his amplifers and that might have cost the price of the amps to install it in his condo
For what tubes seem to do I sincerely believe Hybrid designs are a very good compromise... you take away the pesky and frankly limitative transformer and replace it with good old SS... Question do the Lamm and Tenor use FETs in the output?.. Those have been my favorite Hybrids, although I did find the bass of the Tenor too "light" for my tastes preferring the more robust presentation of the Lamm. I must also say I was taken by the sound of the Moscode amplifiers.. They were very popular at one point but seem to be less so today.. I did like the way they sounded and the sane price... We , audiophiles go throuh some lemming-like modes .. We just follow the brand/s of the day and just drop it/them without much questioning or auditioning...