Black Knight was my first pinball, purchased it in 1988. Nice clean game, playfield has no bare spots, cabinet is in great shape and plays great. Backglass is another story but I know that can be taken care of.
I like many of the newer games, but this game while not complicated, is tough to play and is unforgiving. There are no deep rule sets or fun video modes, it is just plain tough and fun in my opinion. I have no plans to ever sell mine and will probably have it another 25 years or so I hope.
I did reluctantly replace the lights with LEDs, and I have to admit I like the look and I am glad I did. Looks great and operates much cooler which is a good thing.