4 Cylinder is Better, More Power, More Fuel Efficient, More Smooth, Less Vibrations. Thats Y 4 Cylinders is Better. But Age also matters, If a Less driven, Carefully Maintained 4 Cylinder is in access, then its better. Else a 3 Cylinder Car having lesser age will be better. In 3 Cylinder CVT Gears is just a Charm. Smoother Drive, Engine Noise in Less Gear Ratio (Some People Likes that; seems like a Sport Car Sound). in 3rd Gen Latest Shape, Its more Fuel efficient tuned.