Grand Theft Auto: this game is too Mature for young kids (10 yrs.old below) this game is full of strategy,action,violence,sex and inappropriate languages,unlike The Sims,GTA includes a Killing Gameplay (where your can just kill the innocent pedestrians and civilians).no doubt one of the most best selling games in the history of Video game.specially the success of both GTA:San Andreas and GTA IV.
The Sims: EA is definitely one of my favorite Gaming Companies (along with Capcom) this game is also one of the most best selling games in the history of video games,The Sims also include some mature scenes and actions,but! this is a Simulation Game where you get to control your Sims.this game doesn't include Cut scenes with mature languages unlike GTA. as we all know,Sim's languages are called ''Simlish'' and not English,so you won't understand everything they say.this is definitely a Teen and Adult Game
Overall: The Sims win! more recommended,playable for Kids and ''Freedom'' is the word for this game.