I'm gonna play a card, and the card says, "Be heartedly honest."
I don't really like threads that pit Sims 4 against Sims 3 because most of them are just purely petty. Usually, they serve no other purpose than to bring down the people who invest their time into either installment. Other times, however, they serve to bring to light valid issues that an installment has, and I find those threads to be well and good as long as it doesn't dissolve into people being awful to each other for little reason.
Now, I suppose that I would say that I play both games, but I'm actually on the fence about that. I play the Sims 3 mainly, and I have all expansion packs and one stuff pack. Most mods that I play with fix issues the game has, and I have rare mods that add content. I play the Sims 4 very, very little. Opening up a save and struggling to take care of your sim's precious toddlers because your sim won't do what you tell them to will do that to you. I have no expansion packs, no game packs, and no stuff (content?) packs. There are absolutely no mods installed and I have no CC installed either. At this point in time, it's obvious why I play one installment more than the other. But, but, I won't leave it at just that. What I mean is, I have no say in whether one installment is better than the other, because at this point in time I can't compare them. It just wouldn't be fair.
So, one day, when I can grab all the expansion and game packs--why are these two seperate?--for free I will sit down and compare them and form an opinion and perhaps share that opinion with others.
