The Infiniti Q50 was intended to replace the G37 in the brand's lineup. But, unfortunately, it has taken a step back from its excellent predecessor. While the Q50 is quick, an underwhelming driving experience limits its sporty credentials. On the luxury front, fit and finish, ride comfort, and noise isolation aren't impressive. Handling is lackluster, mostly due to the dull steering. Ride comfort is unsettled and suffers from the run-flat tires. The punchy powertrain isn't a model of refinement and fuel economy is not impressive. For the class, the cabin is quite roomy and the rear seat is hospitable, but the front seat has a short cushion. Even more frustrating is the agonizingly slow-responding touchscreen interface.