Non Spoiler Review
Okay. Not as good as Two, probably better than One.
Spoiler Filled Review
X Men 3 (Or X-Men The Last Stand if you want to hold onto the hope that there won't be a fourth) is definitely not a terrible movie. It's not a great movie, but it's definitely not terrible.
It's a movie filled with missed opportunity. Or, more specifically, a movie that spends lots of time setting up characters/situations/conflicts that it never fully resolves (or, even, intends to resolve).
Example One: Ben Foster as Angel. A great character, played by a great actor, with great potential. They open the movie with two short prologue scenes, one of which is younger Xavier and Magneto visiting a young Jean Grey. The other is used to establish the character of Warren Worthington. Fine, I thought. He's getting a prologue before the title credits. We're seeing him before we even see Wolverine. He is then given precisely fuck all to do for the rest of the movie. He exchanges maybe two lines with the other X-Men. By the end of the film I wasn't sure whether Storm or Wolverine even knew his name.
Example Two: A recently revived Jean Grey, when Wolverine brings up the notion of Professor X having suppressed her powers in the past, says "How can you be sure he's not in your head right now? He's tamed you." (or words to that effect). An interesting question. The idea that a psychic of Xavier's powers would use them to suppress or control those mutants he viewed as useful is a fascinating one, and one worth exploring. Then, after the question is posed, nothing is done with it for the rest of the film.
The whole thing is littered with this sort of stuff (don't get me started on The Multiple Man). It all comes down to the film having more ideas than running time. One can't help but think that it would have been a stronger film if it cut one or two extraneous characters and subplots and concentrated on its strongest elements.
Characters from the first two who get completely dicked for screen time: Cyclops, Rogue (whose arc for this film sucked, by the way) and Mystique.
Characters from the first two who continue to get arguably too much screentime: Wolverine and Storm.
Characters from the first two who get their screentime increased, and deservedly so: Colossus (only just) and Iceman. Shawn Ashmore as Iceman kinda takes the ball and runs with it, finishing the film as one of the more likable characters.
Surprises:
Kelsey Grammar as Hank McCoy. I had no qualms with it. He's obviously not really an actor cut out for the big fighting and jumping scenes, but those bits are handled by wires and computers and stunt doubles anyway. An actor like Grammar is hired for his voice and expression, which he carries off well.
Surprise 2 is Kitty Pride. She actually gets to save the day and take down one of the big villains, and does it in a believable and entertaining way.
The effects:
In most parts adequate. Even great in some parts. The ball is dropped occasionally, but I was kinda willing to let that slide due to the sheer number of different mutant powers they were dealing with.
The Dialogue:
Serviceable for the most part. Horrid in some parts.
Looking back over what I've just written, I seem to come across overly negative. I don't mean to. I did enjoy the film. I never looked at my watch. Most of the action setpieces were just great, including a fantastic fight scene set inside a house that Jean is tearing apart with her mind piece by piece. The Danger Room scene that opened the film was good fun. Seeing Colossus in action was a thrill. It's just that the little disappointments are sitting in the back of my head, being all... disappointing. I can't help but feel that they keep this Okay movie from being a Great movie. Because it easily could have been, had the screenwriters and Ratner focused on what worked instead of trying to throw as many showy moments at the screen as possible.