There is no "BEST CHAR EVAR" good Hibiki.
Each character is the best at *something*, because believe it or not, ESF is quite balanced.
Goku is a good all-round character, hes good at just about everything.
Vegeta is a good beam spammer after he transforms.
Frieza kicks ass with the new melee, because you can toss 'em down and give them a few good lasers to think about.
Piccolo has a weak transformation, so to make up for that they gave him the SBC, which of course Cell has as well, so Piccolo has no advantage at all unless you like the scattershot.
Krillin is weak before the trans, but afterwards (if you EVER find a transed krillin in the current 1.2 . . .) hes pretty sweet. 1.2.1 should yield a better krillin playing filed.
Trunks has his sword and early transform time.
Gohan dosn't have a sword like trunks, so he has more speed instead.
Buu has great speed, a candy attack, and extreme speed after he transforms.
Cell has other people's attacks, and some good speed, but a crappy transformation (imo)
Thats all of them, each with their special abilities and advantages for the most part. 1.2.1 should bring more fairness to the higher transforming people, and balance the game further.
I voted Goku because hes the best all-round character, he can do a bit of everything.