I'm working on the same decision right now, with the debate being way harder than I expected. I also have the third option of none.
I stopped at a place I knew had the Pro tonight and played it for about an hour to try to help my decision. In short...
The Pro's art package is by far the best of any version to me. I'm a huge nerd when it comes to Ghostbusters, and the art on the Premium and LE I simply don't like half as much.
I may be a weird-o (I am), but I like the weird ramp on the Pro. Having said that, the Pro that I was playing, the ball kept getting hung up on the switches if you hit it up there from the right entry, which was annoying. The overall light show and sound package is outstanding on each. The Premium I also like the weird ramp on, but I like the right ramp just a bit less than the "same ramp entry". I need time on a Premium to understand the rest that I like or don't about it.
Having said that, I'm still figuring out if it is a great game for me or not. I mean, I feel like I should own one because I have so much Ghostbusters merch that I intend to showcase in my gameroom, it seems like a lost opportunity not to have the pin transition the room together, but I think what bothers me about it is the game is extremely, extremely right flipper heavy. The left flipper basically has the right orbit, and... the ramp if you can hit it, and that's about it to shoot for. The right flipper has everything else. On top of that, the game is tough to trap the ball, and it seems to feed the left flipper a lot, meaning that you have limited shots to shoot for and a lot of the left flipper misses are really dangerous.
I bring this up because you may want to try to do some searching to play one first. After an hour with the game, even considering myself one of the biggest Ghostbusters fans in the world, I'm no closer to fully knowing if the game is for me or not. If it's at all possible, this seems like a good one to get some serious time on before making your call... I hope to spend a few more hours in the next week doing just that!