I only play vanilla & only experienced playing both Sims 3 & 4.
In Sims 4 I can build almost anything I want with any shape I want. Give my sims any occult & other skills/traits I want. Make any of my sims a hybrid. Have fun with relationship of all kinds of sims & go to any festival I want. Raise up their Career levels in seconds. Have a farm.
In Sims 3 Color almost anything but not build very well. Pick a car or motorcycle to drive. Ride Horses/Unicorns, play actual Fairies & Genies, Time Travel & live in the Future.
So, basically Sims 3 & Sims 4 are apples & oranges. However, Sims 4 is a bit better than Sims 3. Once the missing elements from Sims 3 go into Sims 4 then it will be way, way better.
