My first couple of online brawls (aside from the wait time, probably because servers are swamped) went off without any hiccups or much slowdown. There were one or two battles with laggy gameplay, but after a person left the room, it resumed to its speedy brawl. I'm hoping the server problems die down after a week or two, after things settle a bit. I'll just unlock more thing in the meantime.
But first, I need to rest my thumb. It hasn't been this sore in a long time.