I have the GoPro Session and love it! I use an external USB battery pack because my rides are generally 3 hours or longer. The battery pack sits in my saddle bag and I run a USB cord from there to the camera.

I have it set to 720p and 100FPS and the video is crystal clear!

I've previously had and used the Fly6, the Shimano CM1000 and a Garmin Virb..

I highly recommend the GoPro Session!