1. I just started 2 weeks ago. I love it!
2. Best physics and overall gameplay of any sim I've seen/tried.
3. Cheaper than a lot of other sims. I mean $32 and you get all of the content, that's a good deal!
4. Low, low sytem requirements, still giving amazing graphics. I run a stock Gateway slimline that's 3 years old, with integrated Intel graphics, yet I. Get 50 FPS in most situations. That's efficiency!
5. Great community with plenty of servers and events.
6. (Because 5 just isn't enough) The modability, I haven't seen many other sims that allow you to make skins, let alone completely original content.