The Short Second Life of Bree Tanner came out on Saturday. I was actually kind of surprised that other than the girls at Eyes of Amber are talking about it.
No, it's not Midnight Sun. Yes, that sucks. But, again, she didn't write this after she stopped writing that. This was written before Breaking Dawn, while she was editing Eclipse.
Also, I think you're going to be very surprised by the content included from this book in the movie if you don't read the book first.
Lastly, it's available for free in it's entirety online for a month. Go to BreeTanner.com and click on the arrow to the right of the book (a bit down the page on the right) to open the cover, then use the arrows to turn pages back or forth.
It boils down to this for me: Yes, it would suck to never get Midnight Sun, but, this has nothing to do with that really. It's another Twilight book by Stephenie. It showcases just how much larger than Bella and Edward the Twilight world is. It's dark and tragic, in more ways than you're going to guess. Which makes it something completely new from Stephenie. AND, for me at least, by the end, I definitely have hope that there may be more Twilight books someday. Which brings me back to GO READ IT!!!