I will definately play the Exp Superman the next time my venue does an all same TA game. I have been waiting for a viable Superman to put on a JLA team. I can't really see playing him otherwise. Exp Superman really doesn't offer a whole lot more than the rookie for the increase in cost. Plus, he loses the benefit of the Superman TA.
If I were you, I would go with the Vet. Sure, he's expensive, but you're getting what you're paying for.