Brawl is horrible online. I'll just go back to BWii.
I'd say BWii is an excellent example for online play because the game animates somewhat independently of the online transfer info, meaning it doesn't DELAY FRAMES. I know it's a very different kind of game, running only at 30fps, but it's great to feel YOU and YOUR squad move with the responsiveness of the offline game.
The real delay occurs in inflicted damage. I played with Deguello a few times, we're on opposite coasts, and it typically took up to a half-second to see enemy life meters deplete. I got to move fluidly, he seemed to move fluidly, and there's no ghosting or slowdown.