I can't believe I'm going to say this, but I actually like the pro version the best. The hammer and coffin look like they will slow the play down which isn't always a bad thing, but for a Metallica pin I want speed and lots of it! I really like the track listing also so this might actually be my first NIB if the price is right.
Will hopefully see a semi-decent game play video of the pro version to see how it flows and the premium version. Anything else missing from the pro other than the coffin and hammer?