Wow, sounds like you have a fantastic collection Nino. 

Bally, Williams and Stern for me so far. I do see that growing to maybe a Gottlieb if i can find a Waterworld, Stargate or Street Fighter to play first (had an opportunity to play a Street Fighter once but was to embarrassed to ask to play it    ). Capcom's Pinball Magic and Airbourne also interest me.

I don't think brand matters as long as you enjoy the game, I must admit though that i do see why Bally/Williams are favoured as they are built well and are solid.