The fuel efficiency of the vehicle left the reporter less than impressed. While the Lexus claimed to get 31 mpg (versus 18 for the non-hybrid version), multiple tests by the NYT reporter showed the hybrid actually got far less than that. In fact, the tests showed no appreciable difference at all in the fuel economy of the hybrid and non-hybrid cars.
What's the point of a hybrid car that isn't more fuel efficient? The New York Taxi and Limousine Commission isn't doing anyone any good by approving a hybrid that isn't any cleaner than traditional cabs.
NYT: 2006 Lexus RX 400h: The Hybrid Emperor's New Clothes