Cheers for the good info, It would be great to find a restored one with NOS clear coated playfield, full toy-set mods, LEDs, mirror blades, new cab decals etc etc but I might be waiting for a while.

Not sure if the one I'm looking at is working 100%, what typically fails & what should I look for on inspect?

Definitely need to check that the cannons are working properly as this is a well-known point of failure.