As someone who hasn't read the Thor comics, I have no idea how faithful this film is or how in-character everybody is. But as a film fanatic, this is an amazing addition to the Marvel Cinematic Universe. The viewer starts with little love for the main character, but I (and the people I watched this with) found that his personality was developed wonderfully, and that he's actually a really likeable hero underneath his arrogance and self-centred-ness. By the end of the film, he's one of the most relatable characters. Even the villain of this story is sympathetic, and it really is painful for the viewer to see him lose his way. I was apprehensive about the humans Thor meets- I don't really like romance or 'fish-out-of-water' movies- but they were all rather likeable and behaved realistically enough- well, except Darcy. I'd watch a film about that girl on her own, she's a brilliant cloud cuckoolander.
Some aspects of the story could have been explained better- like the Odinsleep- but most of these mysteries are cleared up with either watching the other MCU films or looking at some Norse myths (which is what this film and it's comic counterpart are loosely based on). I liked the way aspects of Norse legend like Yggdrasil, the World Tree, were incorporated into this movie. Also, unlike most MCU films, this is very character-driven, and I think that is what makes it such a good film. The action scenes are few and far between, but what we see is epic and I think it's done really well.
It's a film I'd recommend to anybody with an interest in superheroes (since it's a fresh breath for the genre) and also for anybody who likes fantasy or family/romantic dramas. There's a little of something for everybody.