I have been playing for a couple of hours today, and so far I actually prefer the Sims 2. Anyway, I suppose the easiest way is to make a list of pros and cons of the Sims 3. However, right now cons are going to completely outweigh the pros. So here we go:
Pros:
-Create-a-sim is pretty good. I like the way you can change tiny little details, but I do find it a lot harder to actually create a face that I like.
-I like the new layout of Buy Mode. The way things are layed out is really good, into rooms and then further categories.
-Traits. They are pretty fun. I still haven't got round to making any completely crazy people but I will

I just like the way you can change their personality so much more.
Cons:
-It was probably just the settings of my PC and/or low settings on the actual game, but I really didn't like the graphics. I was kind of like this when I first got the Sims 2, so perhaps I just need to get used to it.
-Despite reading the manual book etc, I still find it confusing. And the seamless neighbourhood didn't really agree with my computer.
-Why do we have to click to move? I spent a while wondering why the view wouldn't move when I was moving my mouse about haha. Its a small stupid thing, but it annoys me.
These are just my first impressions of the game. But they are bound to change when I begin to play it more. I think I maybe just need to get used to the controls the new graphics and gameplay.