Brawl's tap-jump seems much more sensitive than Melee's, so I turned it off. I played 2 matches as Marth and by the 4th time I was accidently double-jumping trying his SH Fair I said "Screw This" and went into controller options to remove it. I've always WANTED to remove it anyway, but in SSB64 and Melee it wasn't as sensitive.
PROS to removing:
No more accidental jumps while attempting U-Smash and U-Tilt
No more accidental double-jumps while trying to do air maneuvers
CONS:
You can't do your U-B out of a shield (actually you can, but you need to move your thumb really fast, or set jump to Z, L or R, then you just hold up while shielding, then hit jump followed very quickly by B)
If you've learned to play using the tilt-jump, it will ruin your reflexes for a bit.
I don't have any more cons
Since both Cons are a matter of skill rather than options being removed, I feel that learning to play without tap-jump is much more beneficial. If just ONE avoidable death can be negated with the removal of tap-jump, then removing it is always a good thing. Obviously, I feel that accidental jumps are much more damaging to my game than not being able to easily up-B out of a shield.