I've been playing The Sims franchise since it came out. The Sims 2 was a huge improvement from the first one, and this one is even better.
The graphics are fairly realistic, and you have a lot of great options to create sims themselves, including personalities, looks and voices.
The build mode also has a lot more options, although it's still fairly similar to TS2. The best feature in this regard, for me, would be Create a Style/Pattern. It's much easier to coordinate your furniture and homes, and you aren't stuck with the same ugly patterns anymore.
The gameplay itself takes some getting used to, especially if you haven't played any of The Sims games before. However, it doesn't take long to learn the basics and once you do, it's easy to play. One thing about the gameplay, is that it has Story Progression - and even with this option turned off, the sims in other houses you aren't controlling will age, die and if pregnant. have children. I've gotten used to this, and don't mind it. But if you prefer the way TS2 was set-up with regards to controlling families, then the new gameplay will likely turn you off TS3.
Overall, it's a very good game for what it is, and I'd definitely recommend it.