It's quite good. It helps a lot with making minute adjustments to aim that the control sticks can't quite manage without dropping sensitivity substantially.

Let's just say there are people with Gyro aiming out-performing mouse and keyboard users in AimLabs. It truly is the bridge that will allow console users to cross into competitiveness with PC without needing dumb shit like allowing console users to 'lock on' to targets while PC users can't. It puts controller users on equal footing with mouse/kb users, especially for FPS gaming.

When treated as a fine input for aiming, where the right analog stick might be considered a coarse input, it is a really good feature.

Most of the time Nintendo has implemented motion controls, it is a gimmick.