I thoroughly enjoyed this movie. And yeah, as some people have said, there are plot holes. But the story feels very real... it doesn't have a lot of "bling" on it... everything is very simple. Everyday actions become tense, and that's a good part of the movie's charm.
You get easily attached to the characters, and you find yourself wondering what you might do in that situation. It'll make you want to be quiet. It'll make you cover your mouth and sob into your hands (if you're a big ol' crybaby like me) just to keep from making a sound.
If it's a concern for you, the movie is very clean. Not much for dialogue, so no swearing. No sexual content. I was worried it would have cheesy, unnecessary gore; It does not have that. The blood is pretty mild in my opinion... tasteful seems like a weird word to use for blood. But, uh, tasteful.
The star of the show was absolutely the acting. I realize even people giving poor reviews noted how amazing the acting is. There is sign language for dialogue, but even that is extremely minimal compared to most movies. It's truly a different experience to watch a movie that you actually have to WATCH, or you won't know what's going on. All the emotion is carried by the acting, music, and camera work. Phenomenal use of what sounds they do include, in my opinion.
Overall, it's a very cool movie, and not like anything I've seen before. I enjoyed it.