Works well, but it will occasionally start drifting.
I have both an iOcean X7S and an HTC One S for testing. The iOcean has a constant and regular drift, but the HTC only drifts occasionally. Interestingly, the drift on the HTC One S can be stopped by looking down at the ground for a couple of seconds, and you will visually notice it recallibrating itself and the drift will stop (until it starts again.)