First impressions of Sims 3. They turned it into more of a 'game' than a 'toy', by making it possible only to play one family at a time and by changing the time mechanic such that the rest of the neighbourhood ages as you play one household. What's more, there's no magic age-decreaser like in Sims 2 (as far as I can tell) -- everyone gets old and dies. Occasionally in public places. One of my Sims was taking a visit to the library, and another patron spontaneously kicked the bucket. And, rather than the last two games, where a dead sim would fall over and turn into a gravestone\urn, now they don't even touch the floor. Rather, one second they're alive, the next they're a ghost. The Grim Reaper makes an appearance (I'm not sure if you can save people from death in this one, though), and whoosh, they're gone.
All this combines to make the game sort of a chilling experience. Gone are the nutty contraptions of Sims 2; The Sims 3 is more sober and realistic all around. The life goals are somewhat more difficult to obtain, but the mini-goals (called wishes) are generally quite easy, but have suitably small rewards. The result is such you'll probably never obtain your life goals, sidetracked by work or family.
This isn't an indictment of the game, though. It's actually quite good, and a large improvement over Sims 2 (especially when it comes to customization). I recommend it!