I can definitely understand the Napoleon Dynamite comparisons. But I wasn't really crazy about ND - I didn't get all the hype. I tried to find "Jarrod" endearing but frankly I found the character to be annoying.
I've not seen ND, and won't be going out of my way to. As for "Jarrod", in my opinion he's not supposed to be endearing. I think we're supposed to see bits of us in him, or bits of people we know in him. For me at least, some of the humour in the movie is the kind where you laugh nervously rather than heartily. That's not a bad thing, though.
I've been reading all the reviews I can find, mainly to see if they say anything about Morag.
It's interesting to note that they tend to be polarised - they either love the movie or hate it, very few reviewers dismiss it outright. I think that's a good sign - it's making people think, getting under their skin, touching those uncomfortable feelings. As I said a couple of months ago, the movie did that to me when I saw it in spite of having been there while much of it was shot. I'll be going to see it a couple more times at least, and hopefully there will eventually be a DVD. As with every movie there were quite a few unused and shortened scenes, I can always dream of a "director's cut".