I also play The Sims 3 on a laptop and must admit that I envy other people's graphics. Whilst I can play, I do miss out on beautiful landscapes, furry pets and my sims don't look as good in game as they do in CAS. My laptop has integrated graphics, rather than a separate dedicated graphics card as the gaming laptops, with separate cards, were too expensive.
My laptop is also not that portable for I need to be near a power supply. The cooling pad (external fan) that I use to stop the laptop overheating, tends to drain the battery. I also use a mouse, rather than the track pad, to control my sims.
However, I do like playing on a laptop as I can play in comfort. If I had the money then I'd buy a gaming laptop with a graphics card that would do The Sims 3 justice, and enough memory that it would play smoothly. If money were tighter, then I'd probably choose a desktop pc and a very comfortable desk chair