TS3 is my favorite, and I play it almost daily (If I have time) TS4 is my least favorite, I play it maybe once every 3-6 months. (usually if there is a piece of bad cc in my TS3 cc that I don't want to deal with, or when I am contemplating where to go with a storyline ) I usually play TS4 until 1) I get bored.. usually within the first hour or so of gameplay. Or 2) I get annoyed. This happens A LOT. Like when I want to do something in my game that I can't or when something happens that doesn't happen in the other games.
(Some examples - The last time I stopped playing TS4 was after I started the Disney Princess Legacy challenge, and all the kids in Snow White's house insisted on waking up at 3am EVERY NIGHT (and waking the entire household) to cry about the monster under the bed!) UGH! I even tried to age them up so I wouldn't have to deal with it.. and I couldn't! (Some Simmers have told me, I should be able to) but I could not. I changed their life expectancies instead... Which made Sno an Elder. Which sped up the entire timeline (obviously) BUT that was a bad thing. Because Cinderella, the next in line - was a teen and halfway through her teenage years already... (I was supposed to master the cooking skill before she comes Y/A- and was running out of time!) -- and I missed how I can set the bar by how many days for each life stage in TS3..
When I went back to TS4 the next day, I found myself daydreaming of how cute "little Princesses" would be (toddlers) And how much more fun it would be if Ariel were a mermaid... And I started searching for TS3 Disney Content.. and well.. its been about a month, and I'm still playing TS3. I might go check out TS4 today, since there was a new patch added.. just to see if they fixed some minor annoyances (my bassinet won't let me change the color after the baby is born, the monster under the bed wont go away even with spray, ALL my Sims and Houses were erased after the last patch) those types of things.
BUT IMO. TS3 is my absolute favorite. I do wish the family play was more like TS2 though.. but the TS2 irritates me with its how its grid for decor is set up.. like how you cant put a rug in the center of the room.. it has to go on either side.. same with doors. Or that you can't put a vase of flowers in the center of the dresser. Which is really funny when you think about it, because with TS1 (which I still play - maybe once a month (still more than TS4 LOL)) the vases and stuff were already on the dressers.. we didn't have decor options like we do now. We had a rug, a table, a couch, a lamp.. and that was it! There were no clutter options in the TS1
Thinking back.. we have really come a long way!