Starting with what's under the hood, we see two totally different approaches from these Japanese carmakers. Mazda's powertrain consists of a 2-liter making 148 horsepower, a normal 6-speed automatic and AWD. It might almost seem archaic, but it's the one we'd pick.
Meanwhile, the Juke did some soul searching after its first generation. Nissan found that most buyers wanted it to be more practical and economical, so the only engine they currently make is a 1.0-liter 3-cylinder turbo with 116 hp. Despite the displacement being half, torque is about the same, and the 7-speed DCT obviously gives the Juke better mileage.
In terms of the driving experience, the Juke feels like it lacks power and the twin-clutch isn't smooth around town. Meanwhile, the CX-3 is aimed at the keen driver, which means you sit much lower and feel connected to the road. It also far thirstier even than the claimed numbers lead you to believe.
The video review by CarAdvice points out that the two rivals are virtually the same size on the outside. The CX-3 is a bit heavier, but that's to be expected. But once you open the trunk, some huge differences become evident, as the Juke's trunk is deeper and thus more spacious. Neither of these cars is particularly roomy for the passengers, particularly in the back. Picking a favorite basically comes down to personal preference, although the newer Juke does have some nice features.