This chapter was highly impressive, a highlight of One Piece in my opinion. I can live with Ace not being Luffy's blood relative, it's the bond between them that counts. But now Luffy got a strong rival for the title of next pirate king, his own brother.
Anyway, forces seem to be evenly matched, i wonder if we are in for some fights between the big guns of the One Piece world. There probably won't be enough room to show all of it in detail, unless this arc turns out to be hellishly long. So probably all hell will break lose till Luffy arrives, i'm sure that while all the big guns are busy he will be the one to free Ace. Not without fighting himself though. Will be interesting to see who his opponent will be, out of all the opposition assembled there.
I also get the feeling that the strawhat crew will show up and tip scales of this monsterous battle to come.