This is a blog about writers/writing, so I thought I'd add a little about differences between the movie (which I saw last night) and the book (which I read last week).
First, I have to say that, as a Star Trek fan, I loved the casting of Leonard Nimoy as the voice of Sentinel Prime. Old-school Transformer fans might remember Mr. Nimoy was also cast as the voice of Galvatron (a rebuilt Megatron) in the 1986 animated Transformer movie. Those who weren't sure about the voice of Sentinel should have had all doubts removed during one scene in Chicago as the space bridge is being prepared when Sentinel uses a comment that Kirk and Spock used in several Star Trek movies starting with STII: The Wrath of Khan, "The needs of the many outweigh the needs of the few." I can't help but wonder if Mr. Nimoy came up with that idea or if it was the writers.
Anyway, back to the point of the post. First, I found the movie fun, fast, and entertaining, but in no way was it Oscar-worthy. That's fine. I've seen Oscar winning movies that I thought were highly over-rated. The turning of Sentinel Prime was an interesting twist. When I first saw Sentinel in a preview, I had to ask myself why make his face look like it has a mustache. It obviously highlights that he's older than Optimus Prime, but they're robots - they don't grow facial hair. Same with Jetfire in Transformers 2. Why do they have to sound older? Maybe give them deeper and slower voices like you'd get from a toy when the batteries are getting low [chuckle to myself].
Another problem. Why is Megatron so messed up? In Transformers 2, Optimus ripped Starscream's arm off, and Starscream put it back on with no tools. Why couldn't the Decepticons get parts to fix Megatron after part of his face/head was blown off in Transformers 2? That was a bit annoying to me in the book and movie.
One of the big differences in the book was that the book had the Autobot Twins (the annoying little Autobots from Transformers 2). In the book, when Sentinel turns and kills Ironhide, he then turns his weapon on Bumblebee, but one of the twins sacrifices himself, jumping in the way and takes the blast, saving Bumblebee. The other twin goes absolutely balistic and attacks Sentinel. While he doesn't last long, the sheer fury of his attack buys Bumblebee time to escape. I understand why that wasn't in the movie. Too many people would probably have watched that scene and labeled Sentinel as a cinematic hero for offing those two despite his evil turn and rooted for him to win the day.
Another difference, while not as big, is Que - the old-looking Autobot who helped design weapons (assumingly named/nicknamed after the James Bond weapon/techie Q). In the book, it's Wheeljack. Surprisingly when I looked up the credits to confirm the name, the voice credits all say "Que/Wheeljack." I never heard the name Wheeljack being used in the movie or the name Que in the book. While Que was just gunned down in cold blood/lubricant, Wheeljack went down fighting. When the bridges went up in Chicago, Wheeljack went in the drink and was ambushed. He took out one of his attackers, but was quickly overwhelmed. The book also smartly pointed out that separating Wheeljack from the others and Prime from his trailer was deliberate - separate Autobots and humans from their best weapons.
When the space bridge control pillar is destroyed in the movie, it looks like Cybertron may have been destroyed - the book implies otherwise, that it's just sent back. The movie effect looked like it was sucked into a black hole (not at all as it seemed to appear beyond Earth).
Finally (biggest spoiler below). And this was a big twist. After Carly (in her only purpose-related scene) pisses off Megatron to get him into the fight by calling him Sentinel's bitch (great line), Optimus and Megatron do destroy Sentinel together, but Optimus never kills Megatron. In fact, Megatron tells Optimus he's tired of fighting and just wants to find a way home, to rebuild Cybertron without a conqueror's mentality. Optimus is skeptical but lets Megatron go warning that he could become a target of other Decepticons. Megatron seems willing to accept this risk. This could lead to interesting future book storylines. Following the book, Megatron could come back to Earth and ask Optimus for help. Optimus would obviously go (eventually) but always wary of a trap. Following the movie ending, it would just be another Decepticon. I'd prefer a following of the book's ending.
Overall, I found both to be fun and fast. I usually take twice as long to finish a book and need at least one bathroom break in a 2+ hour movie, so I'd say both are worth the time.