No but seriously, I've never played FFVI; which version should I play? Relocalized, Improvement, Ted Woolsey Uncensored Edition, or the GBA version with color + sound patches?
A wide amount of choices, none of them are wrong. Here's a somewhat detailed comparison:
-Relocalization has the most fixes of the big SNES translation projects, barring only a patch with all the bugfixes in one for the most from what I've seen. It's translation leans heavily on the GBA side of things, but fixes what went wrong using all known sources of text, and it tries to make sure everyone has the biggest voice possible. There's also a couple of QoL tweaks like faster Cyan meter and other low-key things. Font could be better, but it's better than you'd think in motion.
-Ted Woolsey Uncensored is the one you want if you're interested in playing the SNES original but without the bull. It's bugfixes are minimal to only the most crushing/stupid of bugs, and the translation remains faithful to the original one shipped to the US with all the screwups and problems in the script fixed. Names have also been updated. That's not to say little work was put into it, quite the opposite in fact because all available sources were used and the uncensoring goes to the same level as Relocalized. Great pains were put into making the best possible version of this project's intent, even fixing the original font. This is basically akin to source ports that try to keep things close to the original experience as possible, like DXX-Rebirth or Chocolate Doom (if you've ever played these).
-GBA is the only place where you're going to see the big new Postgame stuff and new Magicite. However you'll have to patch the heck out of it; it's censored in one point all other versions aren't, the colors are brightened to max (this is a worse problem than on IV and V, as atmosphere is really important in VI), the music is awful at some points, and it slows down a great deal (poor thing probably should've been on DS like Chrono Trigger, oh well). All patches try their hardest, but there's still
spots sometimes where the lesser quality port bleeds through. The translation is improved though some will argue. And as mentioned before, the new screen size will kind of mess with things. Postgame isn't bad if you grind enough though, and the "Odin has speed but Raiden doesn't" thing is solved by adding a Cactuar Magicite (the other choices just give Raiden speed). Also Leviathan is awesome no matter where it is. TOSE tried, but the GBA just wasn't enough in the end.
Just don't play Mobile. PC maybe with mods, but even though I liked V's mobile port I hated VI. It's the GBA release in every way but graphics and UI anyhow.