FYI, I own a premium.
I don't like that the pro has so much going on at the kickback shot. The premium has more diverse shots with the iron throne actually being used. Dividing the mistery shot and the kickback up is a bonus to gameplay.
The upper Playfield adds game elements that just are not possible in the pro and it doesn't slow the game down if you don't flip up there. The ball return time to the left flipper is virtually the same on both games the ball travels further on the pro then it does on the premium so I don't understand how it kills flow.
The added full Playfield rgb lights makes the premium one of the best light shows in pinball.
I did have to spend a hour making the rear diverter work properly. Anyone bitching about working on their pin for a hour is probably in the wrong hobby. Stern is also working on a fix for this issue, so it's not really a good argument.
Money shouldn't be an issue, take the time and save the extra if you want a premium. I say it depends on you collection size if you have many games buy a pro, it will do. But in a small collection save up for the premium you won't be disappointed.