They've hit the mark on the next evolution for the Sims!
Outside of that, once you master the interface and a dynamic, living, breathing world in the Sims 3, the game takes on a whole new level. The new personality traits are a major bonus. Your sims really take on a personality of their own.
Other than the items noted above, there are many other features that can be listed in detail, however I think it makes more sense to explore the game for yourself. Definitely worth the investment!
From a gaming perspective, some things they could have done better:
Negatives:
1. The character models are very close to the Sims 2, would have been nice to see the models evolve a bit further. They mentioned this before release and stated it was a choice to maintain a certain look & feel.
2. Some of the game movement is choppy at times and not as fluid. My guess is that pathing will be patched very soon after game launch as it appears to be the problem.
Positives:
1. Fully dynamic environment! Play, interact and/or explore anything and everything. They have not drawn any lines that would limit you short of your own imagination.
2. The customization mechanics have really been beefed up. If you love custom content, the new in-game features will open tons of options to really bring out the creator in you!
I can't wait to see what's next!