Not including things that could have happened to any car (like a broken windshield) and that aren't the fault of the manufacturer, what problems has your smartie had so far? [And how were they resolved? And who paid?]
Mine (in order):
1. battery was faulty [initially SAM was suspected; all work and new battery paid for by Mercedez/Smart dealership in NYC]
2. headlights set too high [reset twice so far, for free, but I still get brights flashed at me sometimes]
3. door latch, driver's side, failed [replaced by d'ship, but since I was over the warranty, I had to pay the $100 deductible, tho this was offset partially by free nitrogen in the tires]
4. rear window latch failed [cable tightened for free at d'ship]
I also had problems with the gear shifter getting stuck, but some WD-40 took care of that.
It sounds like a lot of tsuris, but on the whole, I'm very happy, especially since it's made for a fun trip and awesome parking.