I'm probably gonna get flamed/questioned for posting about this anime/manga, but I'm going to post about it anyways because I feel like it's one of the best I've read/watched in years, and while it has a large amount of controversial content, in the end the plot is amazing and well worth the read/view granted you can handle what may disturb you.
I just got finished watching Kodomo No Jikan. I've read it too. The story is really good, it almost had me crying many times, and sometimes it's really funny too. The main issue I think most people will have with it is that it contains a fairly large amount of loli fanservice. I'm fairly certain the manga was made to appeal to lolicons, but honestly if the loli fanservice(no hentai, only ecchi) doesn't bother you too much, the story is truly amazing and it's worth reading/watching. You need to keep an open mind when reading it, otherwise you'll probably ditch it right away. It's not mindless fanservice, it has one of the deepest plots I've seen in a manga and really keeps you thinking- you just gotta be patient
Don't watch it/read it if you're under 17, it has some mature stuff in it. If you think you'll be offended by the loli content, or disgusted by it, don't watch it either. And yes, I'd consider it NSFW. There is a censored version of the anime, so you could watch that if you think you'll be offended, but honestly the censorship kinda destroys it because it takes away too many things that are important to knowing what's going on, and sometimes it even makes things seem worse than it really is.
If you look up what it's about, please don't be misled. A google search will give you images horribly out of context(and some that never happened) making it seem far worse than it actually is, and even looking up a description of the story also gives you the wrong idea. I can't go into much detail without spoiling it, but the main protagonist is actually a normal guy and not like you think he would be given you read a description or view a random image out of context.
Lastly, this manga/anime isn't for most of you. If you easily get offended, get disgusted by rather obscene content, or just despise lolicon in general, please do yourself a favor and don't look into it. This manga/anime does get pretty graphic, and I'm sure most of you would be offended. Be sure to watch/read it incognito mode too.
edit: loli means underage girls, for those unaware.