Yass, a friend and I got it on Friday (release date in UK), played for about eight hours (mainly for unlocks), then we had 6 decent melee players over for a Brawl tournament on Saturday. It is, quite simply, the win - although they seem to have killed Samus somewhat, her fighting style's completely changed (especially if smash balls are on). Oh, and they went and gave Falco and Fox, widely regarded to be two of the best characters in Melee, the most overkill final smashes in the game. But onto the good points:
No fucking up-jump, you can turn it off. I can't stand up-jump, it makes me useless at strong up attacks.
You can save snapshots while in-game if you pause.
Marth's standard B-attack is improved greatly, as he could catch anyone who was off the stage quite easily by just sitting and charging it at the edge (it had a huge sweep with the sword in Melee). This pissed me off as well.
On characters: I love Ike, he's probably going to become my main character in Brawl, although I never did like Marth or Roy in Melee... he's got a great variety of moves, including a great pair of recoveries, plus that counter and final smash.
Kirby's still really good (yes, I like Kirby. I can combo quite well with him), although his final smash could be a lot more powerful without being overkill... especially if you play without any items but smash balls (which we usually do, as the rest just get in the way and make the match really unfair - yes, smash balls do that too, but I have friends who for some reason like them... maybe this is partly explained by the fact that one of them plays as Falco :/ ).
Oh, and on Ike's final smash: Anyone else notice that it's pretty much identical to "Lion Heart", Squall's final limit in FFVIII? But then again, it's just following the laws of anime physics
, isn't it?