I've been playing around with Ussopp in training mode and had some fight as him.
I have to say he's really nicely done. He got his hammer, dial (works as counter :), different kind of amunitions, he fakes that he's dead then attack with egg that can confuse etc :D Really fun character.
Also there's my tip: if you try to do ussop's yy up/down y attack then do it like this yyy(hold) then immediately down or up. The other way (as writen in game) doesn't work, but with 'my method' i discovered is really easy.
2bad there's no 'transformations' in game so ussop would go soge king and luffy gear2… but well at least he got soge king as best ulti (the one with movie :P)
ps. it's really worth trying different supports in training mode, coz without knowing how they work it's hard to utilize them. For example it seems like Shanks is really slow, but deals a lot of damage, so he should be paired with characters that can stun/confuse enemy or in some other way make time for Shanks to make his attacks. In training mode his support deals almost half hp :o