Reliability of Big Tube Amps - Your input please..

VAC Standard 220 Monoblocks here - No problemo either, after a few hundreds of hours.

They maintain bias adjustment quite well. My only complaint would be that the KT88's expell a ton of heat directly above the tubes themselves.

I have owned the st-150 and mb 450's The st-150 blew resistors once in a while. A pain because it weighs 75 lbs.
I have had no issues with my mb450's. they do not even run that hot. It is beautifully made. I will say the sound is amazing. It rules the speakers with an iron fist, but sounds smooth as silk. It ranks with the finest equiptment made . I think it is almost a bargan in the current used market. I also own tube amps from CJ and ARC and have had no problems ARC never even blows a resister when a tube blows. depending on how much you listen 6550 type tubes last around two years .

Both are pretty reliable!

Does a tube "blowing" typically burn up a resistor?

Pubul57: It shouldn't, but does frequently on my monoblocks. I believe this to be a flawed design and not necessarily bad tubes.