Compact. It fits cleanly under my Garmin and throws more than enough light to keep me safe without blinding on coming cyclists.
Great addition / upgrade. I have the PWR 700 - battery and lighthead, so it was great to be able to add this into the mix. Works perfectly / smoothly.
The PWR system itself is really cool in all of its modularity and customizability. I recently took this lighthead on a 400 mile ride and it performed great on some gravel roads on a very dark moon-less night. Changing light modes is easy and quick so you can adjust brightness for conditions and conserve battery. My only quibble is I find flash modes for a front light mostly useless, but you can set your own custom modes for this light, which I will definitely be doing.