I'm going to be as unbiased with this as possible, though the chances of me succeeding are very, VERY slim.
I myself don't like the book. I'll start with some simple composition elements first. I had to resist the urge to attack the book with a red pen to help out with some of the grammar. I know Stephenie is more a story-teller than an actual writer, but I'm appalled at some of the grammar mistakes I found. Also, I had a tough time reading it. I found it, with a lack of a better explanation, a roller coaster ride of boredom and interest. I had to force myself through areas. I don't enjoy doing that.
Ok, I'm going to try not to post spoilers. Who knows whose reading. Let me attack the plot and the actual story now.
The first ... oh I have to say maybe five or six chapters (I'll have to go check the book again to be sure) were wonderful. Then, one thing changes, and the whole book went spiralling from the first and only book that I've been more excited for than Harry Potter and the Deathly Hallows to this: Please, please, PLEASE tell me this is a joke ... a dream sequence ... a horribly gone-wrong vision of the future that our darling Alice is having. As I blinked through yet another boring chapter, I found myself thinking "What did Stephenie do? Run out of ideas that she liked, so she jumped online and took a piece of every crappy fanfiction on every site in cyberspace and rolled them all into one?!"
I'll keep it at that. I'm on anti-spoil until the book has been out at least a week.
So, while I DON'T regret buying the book and reading it (I found a few chapters wonderful and a certain scene and the ending three or so pages slightly tear-jerking for my own reasons), I'll put it at this:
If I had the choice of having Breaking Dawn for FREE a day early, signed and presented to me by Stephenie Meyer herself and paying $1000 for a copy of Midnight Sun instead, I'd pick Midnight Sun. Hands down. In a heartbeat.
I've had the book finished for around 24 hours now. I also have two best friends on the verge of finishing the book who have the exact same opinion.