if you get anything over $1500 for a SMB, consider it a gift (for the seller). None of the gottleib system 3's except stargate go over $1800. most hover around the $1000-1200 range often. You pay 3k for any gottlieb DMD, and you will be taking a hit down the road.
As far as batman machines go. You really can't go wrong with any of them as they are all fun in their own way. I do like Batman forever the best out of all 4 of them tho.