TBH it's not like they all fell into my lap and were museum pieces.
First one was a $150 10PM craigslist buy, two others were $50 arcade converted specials that were filthy and needed a cleaning before I was able to sort out a bad tracking potentiometer and dirty optics and this one was a gift.
For a top loader they are fantastic. Reliability wise they beat the pants off the Magnavision and are easier to service than the PR-7820.