I currently own Iron Man and Star Trek, and a friend just bought TNA. So out of the 3 of them, I've definitely played TNA the least, but I do like the game a lot. It's like the best classic Stern ever made. I'm sure I will own it at some point.
I wish I could rate TNA properly. It is an ass kicker with that classic feel. It was the first game Spooky did that I didn't hate. There is something about the surprising speed of the game. So I will say it is a good option.
Iron Man is fantastic. I love the game because if I only have 10 minutes, I can get 3 games in on it. And as I said in a different thread, I swear more at Iron Man than any other game I own. It provides pinball satisfaction quickly. The rules are easy to understand, but accomplishing what you need to do is tough. However its weakness is being set up wrong. If it is set up easy, there isn't enough to keep it going. Getting the Do or Die hurryup every other game, and taking that right into Jerhico too often becomes boring. It needs to be setup nasty to be fun.
Star Trek, well another game I love, but for different reasons. It is more complex, and a bit more strategic than the others. You can play the game multiple different ways, with different strategy. Some more rewarding, but with a bit more risk of a bad score if you fail. I really enjoy the game, but it isn't a butt kicker. It is a fun romp. The deeper objectives are difficult enough to remain interesting. Overall a winner, but I'm not sure that is what you are asking for.