So after a good deal of trying I finally managed to get a game of random people online Brawl going tonight. Once I finally got connected to people, I had no problem staying connected until I was booted off about two hours later (time flies when you're having fun).
Out of all the game I played I did have a few that were laggy and a few in particular that were just unplayable. After the first unplayable match I started trying to figure out why this happens and this is what I figure.
Big stages make the game go slow.
Seems obvious but just in case people don't know, I'm pretty sure this is the case of the lag. On the smaller stages I rarely had lag and when I did it wasn't really that bad. On the medium stages I had lag a little more often and I *always* had terrible lag in the larger stages.
So when you're choosing your stage for Brawl, choose a small stage. Don't choose the big ones (especially Pork City) and the stages that scroll around a lot like Donkey Kongs stage. Stick to the smaller stages and you should be more or less fine.
The only exception I found to this rule was once on the Hyrule Bridge stage. This one was the worst I had all night but I think that's only because right after that match I got booted off the Nintendo Wi-Fo Connection.









