Diesel for professionals, diesel for racecars, diesel for everyone

Without even looking I can tell if a taxi has pulled up. It's that rumbling diesel engine pulling up to he curb but never switching off. Most people, including myself until recently, thought that diesel meant smelly, noisy and (worst of all) slow. But the popularity of the diesel engine in two very important sectors of driving raises the question of whether or not it is in fact inferior to other