My impressions thus far:
The camera is sensitive to high frequency vibration if mounted solidly to hard parts on the bike. This causes a wavy look to the picture, which varies depending on the vibration (changes with engine RPM and road surface).
Are you playing back the video on an HD tv or on a computer? The HD video file is a huge resource user and almost all computers are going to choke on the file and will give various symptoms while trying to play it.
If you use the Hero to input directly to a flat panel tv, you may find big differences in the playback quality. Or, maybe not. My computers often have some playback issues but the TV just plays it as it is.
As a guy that was a slave to film cameras for most of my life, I've learned how to live with wide angle lenses and the easiest way is to make it not so wide for average use.
Ultra wide angle lenses will give you a lot of depth of field but they will distort too much for most uses and you will find your horizon either bent way up or way down and that will depend upon where you aim your camera.
If the horizon is at the bottom of your field of vision, your horizon will be low in the center and rising rapidly to the edges of the field and opposite if your horizon is high in the field of vision. The horizon will be curved downward at the edges.
I've played around quite a bit and settled on R5 (resolution setting number 5) for my normal use. It gives true HD in a 16/9 ratio and reduces the wide angle distortion as it narrows the field of view. Even then, try to center the horizon near the middle of the field of view.
Even then, the wide angle does it's thing. I did a video on Ranch Road 337, one of the famed Twisted Sisters, and didn't ride very much above the posted speed limit but with the wide lens picking up the rock walls going by on my right, in the corners, it seems like it is much faster.
A 30 mph 270 degree curve with rocks going by the handlebars looks a lot harrier than it really is, even with the lessened field of view.