Sims 3 is definitely better.
Weaknesses The Sims 4 game.
Despite being a full-fledged sequel, there were still objects and opportunities in earlier sections that just disappeared. I specifically missed the free movement within the city. Simem on foot, by taxi or even with his own car, could get anywhere in the city where he lived. In The Sims 4, it was a huge disappointment that if I leave my home, I can visit some sites but just my neighbors; when I want to go further, I have to wait the same way as in The Sims 2.
There are no cars, no bicycles, no means of transport that can be used by a simmer. Sometimes a car appears in the city or is now a tram, but I can not use them. Jobs have not even been seen in the form of a building, just like a bookstore, a grocery store and other catering or community facilities.
Sims 3 is fun with all accessories. Sims 4 is interesting for maybe 1 week, and then becomes tedious because there is nothing in it.