I see one almost every day here in Toronto. My understanding was that they were originally slated to go onsale this summer in the US, in the ForFour version (we just have the ForTwo here). I heard this recently in the context of why you can't get the 4seater in Canada yet.
When MB originally had demo models here the projected the base price at around $23K CDN. I guess they figured out that no sane person would pay that, so it was introduced at just under $17K CDN. However, if you just want a car as basic, fuel efficient reliable transportation, I have no idea why anyone would take this gimmick over a Toyota Echo at 20% less.
I don't like the Echo or Toyota's much for that matter. I had a Corolla and it drove like a pig. The suspension was made of wet noodles and felt like it would roll on a gentle corner. But the Echo's fuel effiency ratings are barely above the Smart, plus it is a true 4 seater (maybe 5). It is not much bigger but much more practical I would suggest much safer.
I am not a "I only feel safe in a big car." nut and I find that a 2800 pound car with a 94 inch wheelbase is a great size. But I would feel exposed in a Smart, based on the tippy height, tiny tires and zero margin in terms of cabin intrusion.
I have sat in one but not driven it. As a design it is very clever. But it is a car that is capabe of 70mph highway speeds, and I shudder to think of how it would fare in emergency braking (slide on skinny tires then flip) or getting hit. I pass these things doing 70 at least once a week on a road where I was hit by flatbed truck in March. I was hit twice at 70mph, spun across three lanes of traffic and hit the concrete median. Ten seconds later I had my laptop out and was taking notes. Not a scratch, not even shaken up.
That was in a Porsche, not a big 5000 pound lincoln. You can make a strong ssafe small car.
In a Smart car I would have been crushed, flipped, rolled and dead in less than 5 seconds. I might have survived in an Echo. Might.
As an aside, I have drive the Mercedes A series in Europe (it's very popular with rental agencies) and was astonished at how good it was.) Was really surprised that it would easily handle 85-90 mph speed with a 1.3 Diesel. It is more directly comparable to something like the Echo