Never played either. Probably would if they re-released on PS4, but that said a remake with modern graphics would be much more appealing. Sprite based games look a bit dated now. If FF6 were to get a remake just like the one FF4 got then I'd be all over that!
While the FF IV remake is great, IMO FF IV/CT aged beautifully: give it a shot, on a smaller screen with an emulator with filters for example.
...but I would welcome remakes with trophies