Well, the ROM and PSX games arent that different, the PSX has a minor loading time which is definately over exaggerated by people.
I say the PSX version, the PS Controller is better than the SNES, Nice FMV's, You get FFV on a TV instead of a Computer Screen.
The ROM's easier seeing as you can save states but that sucks the fun out IMO. An upside is that its free though.