Okay this isn't much of a review since if you're aware of Super Smash Brothers Brawl then you've already seen the acres of stuff telling you that it's not only the greatest thing since sliced bread but it will actually cure leprosy if you put the game in your Wii and then touch it. So who cares about that? The real question about the game should be "Is the new stuff in it any good?"
For those non-game players Super Smash Brothers Brawl is a game where popular Nintendo characters (and a few guests from other companies) decide to get together and beat the snot out of each other. Really you don't need to know much more than that.
My opinion is that there's enough high quality new material in Brawl that it makes a solid successor to Super Smash Brothers Melee. Differences are always going to put some people off but I am enjoying the larger scope of the new game.
So there's a lot of new fighters in the games and inevitably this leads to fights over "Who sucks more!" Inevitably when I see someone claim that a particular character in a fighting game "sucks" I soon encounter someone who has developed their skills with that character to such a point that they can take on all comers. So all I can do is rate my preferences:
Pokémon Trainer - He's got everything you need in one package. The quick Squirtle, the flying smasher Charizard, and even the more balanced Ivysaur for those times when you need all the angles covered. He's a swiss army knife that can be tough to prepare for. The only two downsides are that you have to master three characters to use him well and that final smash is just a simple beam which can be easily avoided.
Olimar - I wasn't expecting to like the little man from Pikman so much but he's a sneaky one. You can take down the bulk of your opponent's life in moments without them realizing it with his Pikman throwing ability (the little things stick to players and weaken them). When you're followed by a full set to back up your regular attacks they can pile on the damage. He's reasonably quick and his small size gives him an avoidance advantage. On top of all that his Final Smash hits everyone automatically for major smashing damage. I'm not fond of his chain whip attack and his lack of a down special (it simply calls the Pikmen back) doesn't help but this guy can surprise you.
Snake - The best thing about Snake? When the crowd chants his name they do the "Snake? Snake! SNAAAAAAAAAAAKE!!" that accompanies the game over screen to all of the Metal Gear Solid games. Even if I wasn't that easily amused he's got a really strong reach with explosive attacks. His mortar regular attack is particularly effective and his recovery move is easy to use. He's also got one of the greatest final smashes in the game as the game switches to the view of him sniping the characters as they fight. My only two problems are that he's on the slow side (I like my characters faster than this), and his forward special is a very slow rocket launcher which holds you in the attack pose until the rocket is gone. If you miss and it goes off the screen you could be stuck for several seconds.
Zero Suit Samus - Samus becomes the token "Sleezy, hyper sexualized, whip bearing female" for Brawl in this special mode that is only accessable through regular Samus performing a final smash or holding down a button while loading the match. She gets a radically different set of moves like that way which turn her into a speedy melee'er with a good reach on the special attacks.
King Dedede - The massive fighters aren't my favorites but I kind of like Dedede's craziness. He's got a massive reach with his hammer, a few good areal attacks and a fun final smash. I just wish that people couldn't dance around him so easily.
Pit - For a character that flies I was expecting him to be a bit more effective in the air. As it stands he's not a bad fighter with a good variety of moves, but I found his flight to be more of a gimmick than a useful ability. The archery also seemed to take too much time and not be particularly effective.
Metaknight - The first time I played him I was sure he'd be my favorite. His torpedo forward special is great, his counter attack is actually somewhat effective, his swooping up attack works great, and his regular sword swipes are fast. Then as I played with him more the flaws started coming out: the loss of movement when attacking in the air, the fact that all of his attacks are incredibly weak, and his slow walk speed compared to the fast attacks. I still like to use him but I wound up feeling like a wanted a bit more oomph out of him.
Wario - The first time I used Wario I couldn't stand him but he quickly grew on me. His motorcycle attack is a lot more controllable than Yoshi's similar egg roll, and Wario is more maneuverable than he looks. I doubt Wario will ever be my first pick for a character to play but he's fun.
Diddy Kong - I love his speed, I love his standard attacks, but his special attacks redefine the term useless. Both weak in damage and unhelpful in effect the only thing that's even usable in there is throwing banana peals. His pop gun and his rockets require charge time to approach effective and you could spend that same time doing something that is more helpful with his regular attacks.
Lucas - A copy of Ness but the variations in his PK moves give him a slightly different feel. In particular his explosion freezes which can be very effective.
Lucario - Okay, I've got nothing against Lucario it's just that... well... I've used him in matches, I've played through classic mode with him, finished all star mode with him, and I can't remember a thing about the character. He's bland, run of the mill, standard. I won't be shocked if quite a few people find him usable but he's just Mr. Average to me with nothing to make him stand out.
Sonic - He sets a new standard for tough to control characters and his attacks are tricky to follow even when you're the one controlling him. I'll give him some time to grow on me but unless a miracle happens I don't expect my opinion to improve.
R.O.B. - Including the Robotic Operating Buddy as a fighter? Genius! Making him slow, unmanueverable, with a tiny reach, having the few attacks that can go a distance ineffective, and a pointless final smash (he continually emits a small cone of weak damage in front of him for about ten seconds)? Confusing. The best thing about him for me is his ability to fly long distances.
Wolf - They took the time to eliminate almost all of the clone characters with Brawl or change up a few of them to give them an extra special something and then made a clone of a character who already had a clone. On top of that the only thing that makes Fox worthwhile, his speed, is completely removed with Wolf. Wolf is in my bottom tier of characters that I want to use.
Toon Link - He's a fine character, he's just down here because he's presented as a "new character" and it's just "Young Link" all over again. So he's not just a clone, he's a clone we've already had. That pretty much places him at the bottom of any list of "new characters".