Hm, I personally prefer Brawl. Brawl had much more content, and the ability to save replays/images was pretty nice.
And even though the wi-fi is pretty bad, I can still play on it. =P
And I actually liked Brawl's physics better; yeah, it's not meant for legit combos but I hated how fast Melee characters fell, and I love that I can survive for a good while in Brawl compared to Melee. IDC for L-Canceling nor Wavedashing. I guess I'm more of a slow-paced person LOL
Also, Ness (my main!) got a good improvement from Melee to Brawl. He's not as good at he was in the N64 version but I still find him a good character, even though the tier list says otherwise, but IDC for tiers.
For me, I'd say Brawl > N64 > Melee. Don't get me wrong though, I still love the series and Melee was a great game too.