I don't even know what sport it is. Football?
As a Chelsea fan, I have obvious reasons to dislike both, and I know plenty of us aren't even watching this game. I will be, though, and purely for the fact that I can't stand the massive wankfest over United being the greatest thing since the Big Bang, I've edged towards Barca. I also honestly think they will win it, as they'll have far more freedom to play than they did against us. As good as United's defence and attack are, their midfield won't be much of a match for Xavi & Iniesta (the two best midfielders in the world), and the game will be dictated by them. United will get a goal on the break, as Barca's defence is weak, but I think Barca will dominate and create many more chances than they did against Chelsea, hence will get a few more goals. I'm predicting 3-2 or 3-1 to Barca.
Also, Messi shits on Ronaldo. If Ronaldo has a bigger impact on the game tonight, it doesn't automatically mean he's the better player - it just means he can play well against a defence much, much, much, much weaker than the one Messi will be up against.
Can't really think of many better midfielders than the little Spanish magicians. Essien, Lampard maybe, but that'll probably be put down to bias. Nobody else comes to mind really - please don't bring up Stevie "Hollywood" Gerrard, possibly the most overrated footballer in the world.
As for Alves, he's suspended for the final. Same with Abidal. Barca have a makeshift defence, and will probably be playing a midfielder at centre back, a centre back at right back, and another midfielder at left back. The only one they'll have in his favoured position, hence their strongest link in defence, was Man United's 5th choice centre back last season: Gerard Pique. You have to worry for their defence against Rooney & co.
He is a good player and I agree with some of what you said(he heads the ball very well, he is fast, good at dribbling, etc), but you also forgot to mention that:
-He is the biggest diver in the world.
-He is simply mediocre or shitty in most big games (not all big games though, especially recently!).
-He does a lot of useless whacky dribbling attempts when he is not close to the oponent's goal and that makes him lose the ball countless times, making him look like a moron.
-He misses a SHITLOAD of free kicks(but when he scores a single fucking goal everyone goes ''wow can't believe he did that!'').
Most soccer players are assholes anyway, so it's not personal, if in the past C. Ronaldo was kinda shitty, now he is a good, hard-working player that really has improved a lot, but simply overrated tbh.