I understand why so many people like Twilight the best of the series. It is because it is the happiest of the 3 books (so far). It is the romantic (getting to know you) story of Edward and Bella. Most teenagers I've spoken with have mentioned that they didn't like New Moon all that much and I can understand why.
New Moon is a book that dwells on Bella's depression when Edward left her. It is angst-filled almost from start to finish. I went through a similar experience so I could intimately relate with her apathy and catatonia and seeming recklessness. While New Moon is not a happy book, I feel that it was necessary, if only for the purpose of serving as a transition between Twilight and Eclipse. For the most part because New Moon is where Bella actually gets to know Jacob Black and becomes close to him.
I have a confession. While I am enamoured with Edward Cullen, I totally agreed that Bella and Jake make sense, even though Jake is 2 years younger than her (and looks about 25). It's not just the fact that he is more human (because he is). It was something else. Bella's relationship with Edward, the way she acted around him reminded me of Catherine (played by Linda Hamilton) and Vincent (played by Ron Perlman) in the 80's TV series Beauty and the Beast (insert music of "The First Time I Loved Forever") will know what I mean. They were almost always romantic, standing close and whispering to each other, etc. With Jake, Bella was more natural, more uninhibited. More ... herself.
And then there is the difference of cold and hard as stone and warm as the sun. Edward and Jake are polar opposites --- in color, temperature, malleability, temperament, etc.
It is difficult to choose. And I know in the end she needs to choose just one. Poor Bella. This will be a tough choice for her to make.
New Moon, for me, is a "must read".
For those who haven't read the book yet, click here to read the first chapter of New Moon.