Polar opposites--stop & go (TSPP) or really fast (IMVE). Never played IMVE, but with TSPP I was never good enough at it to explore the deep rule set. So nearly every time I played it was Otto callouts, Doh Frenzy (Doh, doh, DOH DOH DOH doh doh DOH), Comic Book Guy hurry-up music, some Daredevil bumpers, a few trips to the upper playfield, maybe Duffman and that would be about it. Ten minutes later and a pathetic score of about 25 million had me thinking I would've had more fun playing something a bit faster paced. As a fan of the Simpsons show, I wanted to like it more, but it just didn't click.

Since you already have Metallica and it can be a bit wood-choppin' (TSPP is that way too, but with more hand-holding for the Chuck E. Cheese crowd where these were routed) I'd go with IMVE.

TSPP is the annoying (music/callouts, even as a fan of the series) and slower-paced version of Metallica, and I'm not much of a fan of their music. Having both is redundant, especially with 5 or fewer pins.

TSPP owners are here and they're a proud lot. Good for them.