Many people here saying CD8 is better than CD7, but how manny of them had a PS CD7 fault and don't know about it.
I'm pretty sure my did not have this problem after ~ 800 hours (my came with the upgrade 6H30 board installed from the factory). Not long before I sold the player, I have put a brand new set of tubes (all 7), just to see how much the original tubes deteriorated with time, only to find out no real difference in sound quality between the two sets.
So, as far as I'm concerned, the CD-7 was one of the best, if not THE best CDP I have owned so far - both sound quality and reliability wise.