It's a fantastic car. I've had mine for about nine months and after having owned an number of rather expensive (and inexpensive) cars, this is probably my favorite.
I've never driven a gas-powered Fiat 500, but I imagine the build quality is similar. It's surprisingly comfortable and well built for a car in its price range. I'm pretty particular about the noise levels in my cars and the electric model is reported to have more sound dampening than the standard model; external noise is probably more obvious when there's no engine to mask it. Quiet, fantastic acceleration, and virtually no maintenance. There's a lot to like about this car.
I hope they continue selling them. I've leased mine since the technology changes quickly enough that I expect better range / faster charging, or both within 3-4 years (plus competition from Tesla in that market segment), but if there were no other option I would definitely purchase mine at the end of the lease.
This is my first electric car, but I can say unequivocally that I will never purchase another gas-powered car (unless it's an exotic / sports car). It really is that much of an improvement over internal combustion.*
*For me. Obviously electric cars are not for _everyone_(yet). If you need to haul bales of hay up a mountainside four times a week, buy a truck.