Finally got a chance to play a premium and figured I'd post my views:
For the differences:
Cab: pro looks way better no question, the premium looks like its a sun faded cab where as the pro is colorful and more detailed - pro
Translite: both are great - tie
Ecto goggles: very meh did do anything for me and I didnt look at them much while playing - tie
Magna slings: I do like the idea, but as there is little difference between them and standard - tie
Models: obviously premium is better here, the models look really great - prem
Slimer: I liked when he was out of the way on the premium but don't like how he drags his butt really brings down the coolness of it, and I prefer how he moves better on the pro - pro
Ramps:
-The prem look much better, are made of metal and I really like the idea of the subway
-The right ramp doesn't feel much different (shot is still very tight) but comes back of course to the left flipper it would be cool getting some loops going on it.
-The scoop is better than the esp shot on the pro since sometimes it comes back out on the pro.
-However on the prem many times if the shot isn't quite hard enough to the left ramp, it wont quite come up the other side and will just roll back and fourth for approx 15 seconds, the ball search will activate etc and eventually it will settle down and spit out the kickout; I found this very disruptive to the game play - where as the pro doesn't look as good, it plays very smooth and fast. - undecided
Playfield colour: the playfield colours are quite a bit different on the prem, darker, and alot more dark blue, both are still very nice but I think I like the prem better - prem
Other:
-If you think its hard to see the PKE lanes on a pro, the premium having a higher left ramp almost blocks them
-You cannot backhand the left ramp on the prem where as I do all the time on my pro.
-I don't know why but I was having a lot of crazy airballs on the prem where as I don't get many on my pro.
To sum it up, its actually a tougher call than I though Id be having I do think the prem suffers in gameplay a bit due to the left ramp but does look a bit more - well 'premium' when your standing next to it