Off. I literally could not even play the demo after discovering tap jump was permanently on in it, and I curse tap jump for my being unable to master melee Marth (I could never freaking uptilt in any hurry) despite even managing to wavedash... On Brawl Metaknight I'd sometimes have it on for Uair auto-comboing or such, but it's otherwise only ever been a nuisance to me...
Also, I had to redo my control setup to feel more 'gamecube'-- Right is jump, Down is standard, and Left is special... with me ignoring Up... I honestly can't for the life of me care to remember which button's which, letter-wise, given their mixing them up, so I just treat them like C-buttons.