Original Cary 300B Monos Reliability?

Anyone have long-term experience with the original Cary 300B monos (with the single 6SL7 tube)? I'm looking for feedback regarding reliability. I've read that the engineering choices made in the design should have the amps failing on a regular basis, along with eating tubes. 

Outside of a few DIY complaint/discussions, I haven't really seen this brought up as an issue.

I'm not concerned about the sound qualities or speaker compatibility as I have heard the combination before. Just looking to see if any of you have experiences to share regarding technical issues. I realize that these amps are now 28 years old, but they are point to point with basic parts. If the chosen values have worked for years, replacing defective caps/resistors should be straightforward.

Thanks for sharing!