I had a lot more typed here, but then safari froze up and I lost it all. I'll summarized my original post.
This is my first Smash Bros game. It's great. I tried Brawl at its release but it's online was broken and I never bothered to play single player. I really enjoy spectating and think the ability to bet is ingenious.
My connections have been completely smooth almost every match. I play four-player "for fun" almost exclusively, with about 50 or more matches under my belt. I recall a couple stutters, but they smooth out. Anyone having connection problems honestly needs to check their own router and Internet connection.
So far, I prefer Villager, Link, and Kirby. I am tinkering with Duck Hunt and Game & Watch, though.