Data Easts are like Toyotas - They don't necessarily look great, but they are very reliabile once you complete the manditory repairs. Flipper Kits are VERY expensive, and plastics sets etc are not as widely available as Bally / Williams. Drop target assemblies are simple, motor/gearboxes are expensive when they need replacing.

MartyJ covered the basics - GI plugs/connectors on the PSU and ALL fuse holders !

I like DE games and I see no reason why anyone looking for a cheap good player would go past one 

You mean they have computer software problems that cause unintended acceleration and almost certain death for the driver and passengers??

I think DE machines are far better than that!!!