My wife has a smart fortwo which she picked up last month. It's a real head-turner, and is fun to drive. The headroom (I'm 6'1") and comfort are more than I expected.
But there are a couple of negatives to report.
The car has already had the dreaded 'check engine' light come on, which, according to the dealer, required some hardware and some software. They never did tell us what it was.
The mileage, well, sucks. Most recently we got 29 mpg for mostly city driving. I'm not sure what we are doing wrong.