So I went the preferred route and read the book first, but only because of the movie tie-in cover and my little crush on Tom Cavanagh ever since we used to watch "Ed" when I was little. Surprise surprise, I liked the book and LOVED the movie! I went to see it during it's VERY brief run at the NYU Movie Theatre, and then waited patiently for them to release the DVD in the states. Finally, I broke down and ordered it directly from Canada, which thankfully has the same DVD Region codes as the States.
Most "Gay" movies suffer from crap production quality and/or mediocre acting, but this was spared from both. On top of that, it's genuinely funny and touching. I liked how Eric and Sam are portrayed as an unaffected couple; most long term couples, gay or straight, do not subscribe to the smarmy or constantly bickering stereotypes we usually see in comedies. Noah Bernett makes a character that could easily have been played as annoying, campy, or maudlin, into one that is natural and sweet.
I actually ran into Tom Cavanagh at a Starbucks near Lincoln Center (I <3 NY) just DAYS after I got my copy and told him how much I loved it, to which he was very friendly.
Increasingly, movies and actors from Canada are gaining exposure in the States, and if they're in any way accurate to the actual experience of living there, I'm immigrating to Toronto as soon as I can get a work visa! O Canada!