It really depends on the job. For most of the raft trips I find the hand held cameras to be superior. I like being able to use the view finder, zoom, and control the focus of the shot. If other kayakers hire me to join their group and document a project the GoPro really gives a 'personal experience' feel to the video.
Ultimately, I like using both. I get more footage with the GoPro, but the handheld offers more control.