There may be some spoilers ahead if you have not seen the movie yet, you have been warned!
I LOVED this movie. Eclipse is my favorite book out of the series and seeing it on screen was s dream come true. They touched on every important scene perfectly and the movie went seamlessly and fast!
The romance scenes (Jake & Bella kiss X 2, leg hitch, and tent scene) were perfect! My stomach was knotted in the right places and I felt like I was going through all the emotions again like I did while reading.
In terms of book to movie, this movie hit the nail on the head. Like I said before, everything that was important and needed to make me happy was there. Also, the background stories of Rosalie and Jasper were pretty spectacular. The biggest difference between the book to movie was the perspectives outside of Bella's first person narrative. We got to see how Riley became a vampire and trained the newborns, and also the Cullen's and werewolves chasing Victoria and fighting the newborns. The action scenes were definitely epic.
Each of the actors stepped it up as well. I was not a Kristen Stewart fan in the previous movies, but after Eclipse I have changed my mind. Whatever David Slade did to "Bella", I hope she keeps it up! Taylor Lautner did a phenomenal job too. I was heart-broken each time he tried to convince Bella that she was in love with him. He also kept my laughing with his sarcasm and quips. And Robert Pattinson, amazing as usual, 'nuff said. My stand-out actor in this movie was Jackson Rathborne. The scenes from the South were just as I imagined, and his training session with the Cullens were fun and action-packed.
My one critique would be that I wish there were not as many extreme closeups of the actors. I felt like the whole movie was being played from forehead to chin and after a while I kept wanting to see more of the bigger "picture" versus the flawless skin of the actors.
Overall, this movie is, in my opinion, the best yet and it is definitely not one to be missed!