The best advice is the advice you will hear over and over again, which one do you like to play more? Pinball is a big hobby with a lot of different opinions.
So of course, I case my vote for Jurassic Park. BUT that is because I am not a fan of Transformers LE. For Transformers, I prefer the Pro, and I always have. I feel it shoots better and is just more fun than the LE.
Jurassic Park Pro is a cool game, but is really a players game in my opinion. Better players that love a challenge tend to like it a lot more than casual players. The reason is that it can be a little tough and unrewarding for someone that doesn't want to go deep on the game. That isn't a knock on it at all, I think it is a very fun game. But you need to be in the mood for that kind of game. The great part is that others may disagree with me and say it is a great casual game. I just think it is a bit more serious than other games.
BUT again, those are just my opinions. If it came down to adding one to my game room, it would JP Pro, because I have Transformer Pro already. But even if I didn't, I'd still lean towards Jurassic Park, because it is a better game.
So then we come down to the real question, which is which one you like better.