I've was in your shoes last month and I really tried to justify the Premium. I wish they threw in RGB's LEDs throughout the game to enhance game play. I own a JJP DI and JJP knocks it out of the park with their RGB LEDs. In the end I couldn't give Stern 1700 more dollars for what is already a good game and went with a Pro. Now if they had a lower/upper playfield....or another lock mech....I've done it in a heartbeat. Stern still got my $ but not as much as they could've.
Another aspect is to look at mods...upgrading shooter rod, speakers, external volume control, etc. that you could make either trim package better.