Well, "the original" is the base game and Generations is an expansion pack to the said base game. (I assume you mean "The Sims 3" game when you say Original.) So you can't have Generations without having the original game.
So, I don't think it's possible to compare which is better or worse. Generations adds more interactions to all life stages, but I already enjoyed raising children etc without it. If you read other threads about this expansion, you'll propably be able to decide if it adds something you would like to the game.