From the Tesla press release:
It is incredible that the fastest accelerating vehicle you can currently purchase is not an exclusive, multimillion dollar sports car, but a practical family sedan with spacious luggage storage and comfortable seating for five. I can't think of a car where the phrase 'you can have your cake and eat it too' is more apt.
It's noteworthy that, with only a decade of development, a small, startup-like company is producing vehicles that have all but overtaken combustion engine powered cars not only in terms of performance, but in practicality and safety as well. This, more than anything, is evidence that the internal combustion engine is on its way out. We're only just getting started with electric vehicle development, and it's already obvious that the fundamental technology is an order of magnitude better than any fossil fuel powered car before it.
Having said that, electric vehicles will not sell on the virtue of being electric cars alone. Why has Tesla succeeded when other electric vehicles, such as the Nissan Leaf, despite being thousands of dollars cheaper, have failed? Because the Tesla is a great car, a product the consumer aspires to own. The Nissan Leaf, on the other hand, is a showcase of the potential of electric vehicles. But is it a great car? No.
Manufacturers must ensure that electric vehicles, first and foremost, are great cars. The design must take full advantage of the electric powertrain, and the company must also go to the effort of providing supporting infrastructure to alleviate any perceived shortcomings such as range anxiety. To this extent, the electric vehicle cannot be sold as a 'trophy' car used to demonstrate a company's or the consumer's ostensible commitment to the environment, but rather must be a vehicle that is sustainable, livable, and is practical enough to be used every day (and of course is envrionmentally friendly). Tesla has done this by going to the effort of developing an extensive network of 'Supercharger' fast charging points, and by using the extra space offered by the electric motor to substantially increase luggage space and safety via a 'front boot' and a much larger crumple zone.
Every electric vehicle will be more environmentally friendly than its combustion engine counterpart. Of course it will, as that is the innate nature of the powertrain itself. But what will distinguish a successful electric vehicle is whether it is a great car. At the moment, only Tesla, and perhaps BMW with its i3 and i8, meet this standard.
An electric car being environmentally friendly will be as much of a selling point in the future as a petrol car having fuel injection is today. Effectively null.