Well the thing is, I can connect to Wi-Fi, it's just that in With Anyone mode, when the match is about to start (where is says "ready to Brawl"), it not only freezes, it creates a really annoying sound, and I have to manually turn off the console by either unplugging it or holding the power button.
I've found that it would freeze if I used the Character Swap, which is kinda useless anyway, since it thinks that you died in a match.
I haven't tested it against friends, but I'm guessing the same thing happens.
Also, I had Brawl on for a while, the demos were running, etc. But eventually, I turn on the TV to find that it's just plain black. And once again, I gotta turn off the console manually.