There are subtle differences but of course the basics are the same. The orientation of mechs and general build of Ballys will remind you most of the Williams games. Gottlieb differences will stand out but you'll adapt without too much trouble.

In my opinion Williams games are easiest to work with, usually easy to get to everything, the relays are super easy to clean and identify switch gaps. Bally's are my least favorite to work on because the logic always just seems weird and there's always a bunch of relays in the back of the cabinet you can't get to easily (always the ones you need to get to of course).

Gottliebs are a bit of a pain the ass, always having to remove pins to get to the relays properly, and those relay reset banks that are virtually impossible to accurately clean and gap without taking the whole unit out and turning upside down. Their latch trip relays are also a legendary pain in the ass with their tiny travels and seeming allergy to staying in proper adjustment. And of course their horizontal score motors were also designed to annoy and piss off techs.

Still I'd probably put Gottlieb at number 2 in the "which I'd prefer to work on" behind Williams and ahead of Bally.

I had to go through a Blue Max and get it running, It didn’t really seem that bad. Once I got it working it stayed working.

The biggest issue was lack of availability of coil stops for the score reels.