You should avoid the Tesla Model S, BMW i3 and Nissan Leaf.
If you want to buy the best EV on the market, it is hard to argue against the Tesla Model S. If you can't afford a Model S, you may be looking at a Nissan Leaf, or if you want a luxury badge, a BMW i3. However, you may want to think twice before purchasing any of these models second-hand. Certain years of the i3, Model S, and Leaf have made their way onto the Consumer Reports list of used cars to avoid buying. The i3 is considered to have below average reliability, while the 2012, 2013, and 2015 Model S were rated "much worse than average."
For the Leaf, only the 2013 model made the list as Consumer Reports changed last year's designation from average to below average. The Chevy Volt did not make the list, which should make GM fanboys happy. Also omitted from the list was any Toyota models. Yep, Toyota must be THAT good. EVs are still pretty new, so their reliability over time is still a bit of a question mark. If Consumer Reports is to be believed, some of the early EVs may not be the most reliable cars on the road.