I don't think I mentioned that I got a Wii. Two of my good friends, Brian and Jay, bought me one as a wedding gift, and, well, they couldn't wait to give it to me, so they gave it to me a few weeks ago. The real reason they gave it to me back then was so that I could play Super Smash Bros. Brawl with them (Brian even lent me the money to buy Smash).
My initial impression of the game was at Jay's house, before they even had the Wii to give to me. He had two Wii Classic Controllers, and I tried to play using one of those. That just wasn't going to happen. This game must be played with a Gamecube controller (good thing I brought my Wavebird).
A little bit about my history with the Smash series. I played probably 2000 hours of Classic Smash for the N64 with Bryan and Ryan. We were absolute experts at the game. We could play as Luigi (worst character in Classic) and destroy anyone else. Then Melee came out for the Gamecube. Try as we could, Bryan, Ryan and I could not get used to the new game (windup smashes and spikes, weird sound effects, jumpy gameplay). We went back to Classic, while Brian and Jay played Melee.
Once I got the controls down, I proceeded to set my character to random and just play. The more I played, the more I realized that Brawl plays a lot like Classic (Brian tells me the game engine for Brawl was based off Classic's, not Melee's, engine). The balance is good so far, the sound effects nice. So far so good.
Online play is kind of hit or miss. Sometimes lag enters the game in a really annoying way; the game will simply slow down until the consoles are synced up again. Sometimes it can get really bad. Other times it will be perfect. I played a three-person game with me in Boston, Eric in NYC, and Adam in Wisconsin. About 30% of the time it was perfect, 40% somewhat laggy, and 30% one of us dropped out (with either 2 there was almost no lag). I have yet to play random people online.
More as I see fit to post!
Update (5/1/08): Two things I wanted to add. I tried for about 20 minutes the other day to play a random game online and was unsuccessful. The UI isn't really helpful or responsive either.
Secondly, I played my first 4 player game last night (Brian, Jay, Bryan). I have to say, I was underwhelmed. We were all the same relative skill level (Brian the most technically competent, Bryan the most strategic, and Jay and I average), so balance wasn't a problem (I even won a game with Ganondorf, so you never know about balance). It was just "eh". Take that as you will.