With a manufacturer-reported range of 220 miles, and a price tag of over $100,000, the Tesla Roadster is not meant for the everyday driver, but for a specific subset that wants to enjoy the feeling of driving a roadster without the associated carbon footprint of a low volume high compression engine. Tesla Motors has scaled back its claims in recent years with regard to their launch date, transmission options, and even revised launch dates as they continue to experiment and innovate - and it's okay for them to have setbacks because we all know designing a custom product will have unexpected pitfalls.
And then there's General Motors. Chevy's entry into the market is quite a break from the pack of electric cars: built on the company's new global small-car architecture, the five door hatchback has a planned 40 mile range, with a small internal combustion engine as a backup when the lithium-ion battery runs low. At a suggested retail price of $48,000, the Volt isn't exactly cheap, but being a part of the GM lineup does mean that this vehicle will meet all of GM's durability standards, have all the usual GM safety features, and come with a GM warranty - something that Tesla Motors, started in 2003, would have to work hard to match in safety and reliability.
The question, then, isn't one of outselling one another, or even competing with one another in the market. The specific niches each one has been designed for aren't too hard to figure out from examining a list of features; the hundred thousand dollar sport car will go to those that are buying a third or fourth car, while the volt will be picked up by those considering a second car with more of a mind for practicality.