The one on Ebay I have seen is a complete wreck and already well over what it is worth. The cannon assembly (the **only** fun thing about this game) is some sort of hack replacement. I am not certain there are any proper replacement assemblies around, Nug did source  repro for his but it was terribly made. The playfield needs more than minor work, and there are lots of other broken bits visible. Add to that the seller hasn't tested it, who knows what works and does not - you might have board problems and need a new DMD for example. At the price its at now (over $700) you only have about that much again before you start to hit its working value, and I can see more to spend than that already just from the photos and guessing what else is not going to be in good condition judging by the harsh life its had.

Gameplay on this title is average anyway. It's getting more love these days as people spend more time looking at older games with the lack of new ones, but it is a very average machine.

I agree. The playfield has more than "a bit of wear" and it is already an expensive project (why do people bid so high?). It can be restored, but it looks like it will need extensive playfield work (or replacement) and it will need a cannon assembly and the other parts mentioned in the auction. I'll bet the DMD is faulty or dead as well (common on untested machines).