i would go IM. it's a faster game and the code is better right now. If you like slower and hit shots, go with Batman. I like both, but I find batman is a bit of repeat and make a bunch of shots lit up. IM is more like adrenaline in pinball. The code is better in batman than 6 months ago, but of the minor villains there are still more needed in season 2 and 3 i think.
don't know if you played star wars, but i would consider that right there with both of those 2. for the money, star wars pro is a better value than batman 66 premium.