Better than average for Hallmark, but...
This was, as everyone else has stated, a beautifully filmed and crafted movie. And it's not super sugary sweet, the characters have a certain depth and it's just a feel-good way to spend your time.
Having said all of that, the most distracting thing for me was, when looking at the photos in the original book and the ones that were used to create the new 'our' book were obviously taken by somebody other than the two people in the photos. For instance, when they're kissing in the 'new' book, who took that picture? And in the old book, who took the pictures when they were out in the middle of nowhere camping or riding their bikes down a street?
Anyway, the minute I started asking myself that question, I sort of lost full interaction with the film.
Other than that, a good movie.