I'm starting to think there might be some "host advantage" in online play. Because when I have hosted, I feel I can pull my combos easier than when I'm the 2nd player for some odd reason.
Several times when I'm the challenger, the first player is able to pull most of his combos even with lag. But in my case, I'm missing them a lot, even the simple ones.
Also I haven't been playing online on my PS3, since I'm not at my house and I'm using my nephew PS3 to play, but I still find this quite odd.