Upon purchasing this game, my expectations for it weren't really that high. I'd played past games in the series and I'd always thought they were okay at best. I was a bit excited since I didn't appreciate the dark and gritty path the series seemed to be taking with Grand Theft Auto IV, and this game looked like it took itself a bit less seriously.
I was prepared for an okay game that I would enjoy enough to justify the $60 purchase. What I got was the most enjoyable and polished experiences I've ever had with a game. I really can't find much bad things to say about the game, it's near perfect in almost every aspect you can think of. Gameplay, graphics, story, sound, etc. Before I knew it, I had finished the main story over the span of 5 days. Simply put, this is an amazing game that everyone should play.
As for the kid-friendliness: there is none. I'm a strong believer that video games do not cause violent tendencies in anyone (except the tennis minigame maybe), but I do think that this should under no circumstances be played by any child under 13. Hell, even I was offended and disturbed on multiple occasions.
Most of the inappropriate content takes place in the story missions. I mean, running over pedestrians is nothing compared to Trevor's fully exposed man banana. Most kids understand that the citizens in the game are not real people, and can't feel emotions like sadness, pain and hunger. You can run over enemies and innocent bystanders, shoot people with guns, punch them in the face (which is hilarious), and much more.
Upon shooting or hitting someone, blood spurts from their wounds. You know, the standard affair. As far as I know, there is no dismemberment of any sort in the game. The most violent part I can remember is a mission where you torture some guy. You can also do good deeds, such as stopping robbers, returning stolen items and driving inebriated people back to their home. Those are things that you're not going to hear about on the news, though. There are strip clubs, but you can avoid them and are never forced to enter one. In the strip clubs there are topless women. Although their breasts look like something from the Nintendo 64 era.
As for the drug and alcohol use, both illegal and medical marijuana are consumed, as well as alcohol.
Finally, the swearing. There's a lot of it, and pretty much every swear word you can think of is in the game somewhere.
My final conclusion is that this is a great game, but I don't recommend it to children under 13.