Oh well, I know I'm in the minority when it comes to FF2 so I won't bother trying to convince anyone, but I sure had a good time with it. I've only played the GBA version though, so if people here have only played the NES/PS1 version then we probably had a very different experience.
As for FF4, DS version is easily the best. PSP version is a broken mess of a port from the GBA version, which was also a broken mess.