I am going to throw my word in here for what it's worth.
I like Lucario a lot. He is really cool, with a lot of fun and useful tactics at his disposal. He can use the Double Team attack to counter like Marth or Ike, really useful arial attacks, such as the down one, which not only does decent damage, but can also slow your fall, allowing you to disrupt opponents below you trying to time their juggling attacks and upward smashes. Then of course there is quintessential Aura Sphere, which is useful for almost any situation for numerous purposes. Just don't waste time with it against Rayquaza, as for some reason Ray seems to have some defense against it, and takes relatively little damage from it. Lucario seems to be fit for a guy like me, who likes to do arial combos and use a nice approach game(I used Dr. Mario in Melee; it's a sham that he isn't here in Brawl), while also having the tactical options provided by his specials and other such moves.
Then I played Luigi. I would like this to be one of those moments where I can say, "'nuff said," but that obviously isn't the case here, since his name hasn't been mentioned on this thread yet. The reason he was rather unplayable in Melee is because he was slow, floaty and clumsy, with an inapplicable recovery game against any good edgeguarder, such as Marth. Now, if you haven't noticed yet, everything seems to be a lot slower than it was in Melee. There is no wavedashing, and overall it seems like things are moving in slow motion when looked at side by side with a Melee game. A lot of you guys have been saying you can't figure out what is wrong with C. Falcon. The problem is you can no longer do a running Shffle'd arial halfway across Final Destination in less than half a second. L-cancelling doesn't seem work anymore, and the speed at which you travel horizontally through the air has been sharply reduced. Anyway, Luigi can now legitimitely recover using the Green Missile since it propels him a little higher when he uses it. The important part about it is that now you can do a midair sidestep dodge and still follow it up with an Up-B, so Luigi can dodge the edgeguarding while in midair and use his tremendously improved Up-B, which sends him a little higher than before, and then he can move horizontally farther afterward than before. Grabbing the edge has been made easier to do and it happens on the way up rather than on the way down most of the time, so now you won't be made vulnerable briefly while you are up there just before grabbing the edge, as you will have already done that before getting in range of an attack. Some say ZSS will do the edgehogging, but You can just missile over her head. It will be safe to since she won't be doing any edgeguarding attack while she is hanging from the edge.
Now what about his actual combat? Well, if you know what you're doing with Lucario, then Luigi should come easily. The difference is, Luigi has a wealth of setup moves that Lucario lacks, like his down and up throws, his upward tilt-A attack, and as a surprise attack, the Down-B tornado move as well. Did I mention that with a repeated B-tapping, that now makes Luigi float up about as high or higher than his actual jumps?
His arial attacks are all superb. All of them but the downward one are quick, with higher priority than many attacks. They all have excellent knockback for such quick moves, easily capable of KOing guys that are under 100% when used effectively. The downward one is relatively slow compared to the other arials, but has high priority like the others, higher than Wolf's upward smash I believe, but I'm not sure. It can be used to smite those trying to juggle you, and still has the knockback of the other arials. Then there is the neutral arial A, which is in its own category. I believe it is the highest knockback neutral arial A attack of all charactersat the very start, unless you include Lucario at 200%. It comes out instantly. I'm not kidding or making an exaggeration, it literally is out instantaneously, like flashing from one frame of a movie film to the next, and it is already out. It sends a guy straight up, perfect for juggling. With opponents at low percentages, it will leave them right near you for you to follow up with another arial in quick succesion. Fatal for most opponents with high damage.
His smashes are very quick, especially the downward one. Not the best range, but the use of fireballs can help with setting an opponent up to be vulnerable for you to get in there and pop one off. His forward smash still has pretty decent knockback, but its range has regrettably been decreased. Luigi can still do some amazing combo work, and his moves do plenty of damage, since they all go rather fast and will likely leave an opponent setup for subsequent arials or smashes.
I'd say I'm surprised nobody mentioned Luigi anywhere here, but I haven't even played several characters yet, so I can understand that. He wasn't as good in Melee at all, not with Dr. Mario overshadowing him, but now he can come out to play with the best of them. I would have really liked to main Lucario with all of those fun tricks up his sleeves, but I can be so much more effective with Luigi. I will last longer too since I don't have to take considerable damage before I am able to knock guys out. So I guess Luigi it is, with Lucario as a competent secondary character.
I liked Wolf too, but I kill myself all the time with the forward-B. Toon Link is broken. First time I played with him, I didn't lose a single life in a five stock match, and it's not like I ever played any Link character in Melee or Brawl as a main either. Zelda is not impossible to beat people; if you avoid her smashes, she is vulnerable while she is waving her arms/legs around.
And also, what is the purpose of Mario's FLUDD attack and Squirtle's Water Gun attack? They don't seem to do anything to your opponent when you shoot them.