One big advantage is if the vehicle is a company car.
Assuming the company will pay for the car (not cheap) you will pay zero benefit in kind until April 2015, and then from April 2015 a reasonable 5% compared to say something like 20%+ for a typical executive car.
So that's a totally free car to the user presently, especially if you charge up while being at work too!
Assuming, of course, your typical daily commute and business mileage is within range, which, I would thought in most cases to be the case.