Revisiting this thread - first of all thanks to everyone for contributing their knowledge and opinions, much appreciated.
I still haven't purchased a new amplifier and have been continuing to look at the used market and researching through various forums. I've looked at some used Prima Luna Prologues, Luxman, Audio Research etc. The conclusion I've come to is that I don't a piece of vintage gear with unknown service history and a lot of the newer stuff is not built to a level that I'll be happy with long term (tube sockets on PCBs for instance). The Ultravalve seems to be the only exception here being new and well built so it is still on the table should I run across a good deal on a used one.
My question today is, after running into a few used McIntosh MC275s on the used market in the sub $5000 range, should I bother with lower priced gear? McIntosh has a nostalgia factor for me - my father had an all McIntosh stereo when I was growing up - so it has always been aspirational gear for me. Is the price difference worth it compared to the other stuff I've been looking at?