Tony the DMD market is/was dominated by Williams Bally but in saying that I own a Data East (Star Wars) and it is extremely reliable . I have heard people bag DE's but maybe they got a flogged out ex-site machine with issues . I'm sure the same has happened to Williams pins as well .
One thing I have noticed that may influence some people more towards a Williams is the availability of spare parts . There just seems to be more around for the Williams Bally machines ( especially in Melbourne in a few weeks time ..
).
Most important thing to go for would be a theme that suits you as well as how deep you want the ruleset etc. (Twilight Zone for example has a VERY deep ruleset which is the attraction for some but a deterrent for others looking for a quick bash-and-play game).
Good luck with your search and remember to keep us up to date with pics of any new aquisitions.
