I was looking at GoPro but The Garmin Virb Elite looks like a very interesting camera if you want to overlay telemetry data on to the video without all the hassles of trying to sync external data sources. The data is stored in standard GPX and FIT files and can be overlaid using the supplied software.

I think it would be really nice/useful to have the altitude, speed, accelerometer (G-meter) and outside air temperature (Garmin Tempe) overlaid on soaring videos as it adds some perspective to the flight. The heart rate not so much unless you're trying to demonstrate the increase of heart rate due to hypoxia.
I'm sure crash investigators would find the footage and telemetry data useful too.

I will wait and see what the critics say once there are enough of the devices in circulation.