Experience bringing older gear up to date ARC, CJ

If you've been into audio for a while, and have pleasant memories of some of the older tube gear (as I do for the ARC D-76a and SP8, or the CJ Premier 2 or MV-75a), you can't help but wonder what it would be like to bring some of that gear back to life, with various parts updated and upgraded, or maybe just replaced (to better keep the old sound?). A key issue would be reliability, particularly with amps, I would think. (I managed to blow up a few back in the 80's--I don't know how much of it might have been related to parts issues, design, or just my own stupidity.) Also, I got the sense, especially in the late 80's, that the tube gear manufacturers might have been fighting a little too hard to get a little too much out of the highs, with not entirely pleasant results. Maybe upgrades would flesh that out.

I'm wondering who's had experience with the "good ol' stuff" brought into the 21st century, and how it's worked out?