The Tesla Model S, arguably the most promising all-electric contender for a slice of the luxury sedan market, was panned recently by New York Times reporter John Broder, who finished his test-drive on the back of a flatbed truck. Elon Musk, co-founder of Tesla Motors, was quick to respond with accusations that the test was not performed under fair conditions. Whatever the rights and wrongs of the dispute, though, one thing is clear: Tesla has some way to go before it can get motorists to buy into its vision of an all-electric no-compromises luxury sedan.