I've heard a lot of things said about The Return sequence of the Vampire Diaries. Some of it was even true. I don't agree with the people who say it's not worth reading, though. There is some silliness in these books, but I think Midnight restores the tone, and brings the series to an appropriate (if a little abrupt!) conclusion. I was gripped by this book from beginning to end -- like the others in the series, it's action-packed and unrelenting, combining heartbreak and euphoria in equal measure. Some of it is a little incredulous, but then, this *is* fantasy fiction -- willing suspension of disbelief is the name of the game, and this book does ultimately reward tolerance of its more outré moments.
Some of this book is (perhaps inevitably) a let down -- Damon's restored humanity was a wasted moment, I felt, but nevertheless in keeping with his character. After being set up as a formidable enemy, Shinichi's easy defeat was also a little grating, as was the miraculous restoration of the town. It's perhaps this that makes the ending seem slightly rushed, but it's still one of the most gut-wrenching I've read for a while.
If you're one of the people who wished they'd left Stefan and Elena at the end of Book 4, then Midnight might just restore your faith in the series. I won't say it's masterful, because it's not -- but it's definitely worth a read. On the other hand, if you're a fan of this series, or of vampire fiction in general, then don't miss Midnight -- it's certainly not as "final" as it might seem!