After having put hundreds of games on Ghostbusters LE, I have to say, that I am 100% sold on magna slings. When you set that leaf switch to a hair trigger activation, they're lively, unpredictable, and a whole lot of fun. I would say about 80% of the time they feel like a standard kicker, but that 20% of the time when they're a bit "weird," they sure do mix things up. I love how John and Dwight came up with the idea that at certain times they would act differently, and I think there's probably lots more space to explore those sorts of concepts in future titles.
I think of a game like Rob Zombie that has a kicker halfway up the playfield and I would love to see how a magna sling in that area would play. I would love to see one near a pop bumper nest that could do some funky things at times.
I was skeptical, even after I had my GBLE on order, but I have to say, the magna slings are a winner and I hope that they don't end up being a one off feature.