I'm a Brit living in the US with my American wife who owned a smart in the UK for almost 4 years.
With sincere respect I have to say that aside from the "Taste" issue, as in they're not going to appeal to some people in the same way that they do to others, many of the comments made about the car are misguided in the extreme.
Someone mentioned the crash video. There've been a few of those and one thing emerges from all the research.
At the speed that the smart is travelling you'd die in ANY vehicle that stopped that quickly.
The smart, however, does better than almost all other vehicles of similar or often larger size in resisting deformation of it's passenger compartment which means that in a 30 or 40 mph crash you're less likely to be injured in a smart than say a VW Jetta or a Golf or another similar sized three door hatchback as we Europeans call 'em.
Ours cruised at 80 on the Motorways of the UK with little or no discernable disturbance from the wind flying off the front of big trucks or crosswinds in general. It easily contained my partner and me on half a dozen camping trips with all our gear for weekends at festies and got 50 plus mpg (UK gallons) even when I was thrashing the bollocks off it.
We were gutted that we couldn't afford the huge fees to enable us to bring it to the US with us and even more gutted that with us both hanging on to our jobs by the skin of our teeth we can't risk buying one here now that they're available. But we can wait a while and snap up a used one eventually, I expect.
I don't know what's under the rear floor nowadays but ours was powered by a 699cc 3 cylinder turbocharged mercedes engine. You could get a slighty smaller engine but we opted for the 699 so's to have AC.
Two minor drawbacks as far as I was concerned were the harsh ride - stiff suspension made for great handling though. Except sometimes it didn't. Push the little devil too hard into a tight turn and it wouldn't. Turn, I mean. Understeered like crazy. But only on an uneven or loose surface. A nice flat tarmac surface meant that this particular problem rarely if ever manifested itself. All the weight is at the back, see. If you were going uphill, and turning hard at the same time it'd push a little more than you'd be comfortable with.
Again, as has already been mentioned, they're designed primarily for pootling about in the city and not for doing the Paris-Dakar. I had to keep reminding myself of that each time I went out in it on my own. They're the best 4 wheeled fun you can have until you can get back on your bike.
And they really are safe. Honest.