ST is the way to go. I sold my Pro and miss it. I would buy a Prem back. Shots are smooth and fun. Deep code with a few different ways to play. It is what pinball is all about.
GB is a turd to play. It is not fun at all. So many cheap drains. The shots are narrow, but unsatisfying to hit. Kids theme that kids hate to play because who ever designed it forgot about that and went for brutal instead of fun on the game play. Good job! "Well my kids love it!" - well your kids must be named Uni and Bigfoot then. The modes are the same old stuff one after another. If you get an extra ball go make a sandwich and come back because that is how long the game will take to tell you you got an extra ball. Are there any references to the actors on the DMD at all? I don't recall. I tried to like GB and would have bought it if it was any good, but I don't care if I ever play it again. People love it, but there are many folks like myself out there who are gentler in their reviews and less outspoken as myself.
I would wait until SW comes out and get a GB then because IMHO it will be the number one game sold to get cash and space for SW. Could be wrong, but we will see.
Xmen is a good shooters game. If you like the theme look at that if you can find a HUO LE for $5000 local.