I agree with Alex. I wouldn't consider the Hunter because of it's age and lack of maintenance.
Both the S2 and Catalina 25 are well designed boats and sail well. I also owned a C25. If a trailer is available with either of them, that would be a huge plus in it's favor. If your boat doesn't have a trailer, then you have to hire a marina to haul your boat and paint the bottom, and that is terribly expensive. That's one common reason why some boats are so poorly maintained.
I'd look at the S2, and, unless it looks bad on the surface, I'd favor it, if it passes survey. But either the C25 or S2 would be a good choice.
I should mention that the C25 has an extremely active owners' forum online, where you can get a wealth of information about rigging, racing, cruising, upgrading and maintaining a C25. Association Forum