A friend gave me the game shortly after it came out, and I immediately hated it. I played for most of two days and then didn't touch it again for two weeks. Then I was thinking that since Kathy was so nice to give me the game, I owed it to her to try to like it. Since then I have played upwards of 600 hours (I'm retired, I can do things like that), and I still don't like it.
First, the careers were very difficult, when coupled with the aspiration goals. In fact, I don't like all the goals at all, I like sandbox play. But then with the upgrade that added pools, the goals were dumbed down. For example, in the writer career, some of the requirements for promotion were things like "self publish four books" but now it's "read books". Have you tried to get a sim to sit down and read a book? Also, there is no time for such foolishness as reading, it takes forever to do the daily tasks. Just eating can take forever, since the sim regularly puts its hands in its lap and sits there looking around and talking to the empty room between bites. If they need to bathe or use the toilet, or if they have a garden to tend or if one of the plumbing, electronic items, or appliances breaks, and they don't have the money to replace it, there's more time lost.
The goals for children are horrible. My sim kiddies have no chance to just be kids, they have to constantly be striving for goals as well.
I despise all the stalkers. I've gotten to where I don't even let my sim make a friend, because that friend will be standing on her doorstep five or six times a day, for an hour or more. Even if it's someone they like, such as a lover, nobody likes anybody that much. My sim might woohoo with her boyfriend, then he leaves, and an hour later he's back. Just standing there in front of the door. I catch myself muttering curses.
I have to say the clothing is better, there are no silly puffy shirts that all my sim children seem to age up wearing. I like being able to put on cosmetics for each type of clothing. I like the multi-tasking.
I hate the loading screens. I don't like how an 8 year old leaps out of the bassinet when you age up the baby. I miss the cuteness of toddlers. I don't like the teens being the same size as adults, though to give the devil its due, EA has now put labels on them when you mouse over, telling what age group they are, which saves my female full adult from the embarrassment of being a cougar.
I do not find the building to be intuitive. I do like being able to pick up the house and move it, but that's about it. Mostly I hate it because in order to see what I'm doing, I have to pan out, and it's all miniature, most of it hidden by the control panel and the infernal prices that pop up every time you try to add something. I lose count of how many times I have to redo porch steps, because the price tag hides the whole thing, and I am always putting them in the wrong place.
I have yet to figure out how to make a male sim that doesn't look like a goofball. A goofball banker, to be specific. Yes, I understand how to make them. But they all seem to resemble Alec Baldwin to a great degree, and not in his good years. I can make pretty girl sims, but they all look alike. The hair is atrocious. I like perhaps 3 female styles and none of the male styles.
I like how fast the game loads. This has been key to the amount of time I've played it. Sometimes you just want to sim for an hour or so, so you don't feel like spending 10 minutes loading the game. TS4 loads in less than a minute, and my computer is medium-range.
Mostly, I find that playing TS3 relaxes me, and playing TS4 makes me tense. I have to constantly be working on goals, so there's no time to just sit back and watch the sims do their own thing. I still think EA missed the boat on this one.