Look what Ironman etc does to the mag cores and surrounding wood over time since they are strong magnets.
This has more to do with how flush your magnet core is sitting relative to the playfield. If your magnet core is sitting just below playfield level then every time the magnet grabs and throws the ball it is hitting the exposed wood lip. You have to be very careful when replacing your magnet core especially if it mushroomed to the point there is no space between it and the playfield. If you try to pull it through the bottom you risk and probably will take a good chunk of the playfield with it. In this case I would recommend removing the assembly below from the magnet core so you can pull it out from above the playfield. One more thing to remember is the magnet core has loc-tite applied to it from factory. The best approach is to use a torch to apply some heat, turn screw driver and re-apply heat as many times as needed.
I also came across an old RGP post that people would take their old or even new magnet cores to a shop to have them flatten the face off and add a 1/32" chamfer to the edge to prevent it mushrooming again.
Biggest problem for me is that the flippers are further apart than other Sterns. Often I cradle the ball to slow it down and let it ride off the flipper only to have it drain. Normally the ball would make it to the other flipper. Therefore you need to fundamentally change the way you play to accommodate the larger gap between flippers. That and some shots just seem too tight especially 2 of the ramps. Artwork is awesome though. Overall not a bad game and quite feature rich on the pro.
It was nice bumping into you and your wife yesterday at SB while I had to do a parts run to get sent out to London through my work for a buddy who just picked up a Williams Grand Prix.
I noticed the wider flipper gap on Ghostbusters as soon as I made my first (of many) bricked shots then watching it go SDTM
When the next ball got fed to the shooter lane I held both flippers up to check the gap and it was noticeably bigger. I walked over to the other Sterns in the showroom to confirm it wasn't just my eyes playing tricks on me. Oddly enough I didn't have any problems or drains from letting the ball ride off the flipper to the other or making the main left ramp. I think the game flows pretty well and the only shot I couldn't make consistently was the right ramp which requires a very clean shot if you want to engage more then 1 of the 3 roll over switches leading up to the one way gate. This is probably the only thing I can find fault for in the Pro and it almost seems like it was added in last minute based on the way the ball flows up and down the ramp. By having one less ramp shot or "feature" on the Pro versus the Premium/LE models wouldn't be the first for Stern. I also wish SB didn't have the volume set so damn low as I couldn't hear much of the music or call outs. The overall artwork package is top notch and up there with Metallica by Dirty Donny. I hope Stern continues to use hand drawn artwork as it gives the game a more personal feel to it over the cold photoshopped stock artwork. If you can't afford to pony up or justify >$10k for a Premium/LE model, I think you will be just as satisfied with the Pro model for less. It is pretty feature rich as SuperPinball mentioned above and I'm surprised that Stern kept the two controlled drop targets. That would have meant more money left in their pockets from Pro sales and another up sell "feature".
JT got asked about the wider flipper gap in a recent Forbes and here was his reply:
I don’t know if it was a conscious effort on me to actually open the flippers up on purpose just to open them up. I felt that the outside drains had, even if they were open, they just ate the ball so much. This way I kind of hoped, I guess, to give you some more adjustments to put on the outside drains. I like the way the games play. When you go down the center it’s just too bad.
There’s also the timing of the game. We do still watch the time. We don’t want the guy to sit on there for ten minutes. But then again, we don’t want them to be done in thirty second either. I guess that’s my style.