Looks like the quality has been taken out by the compression to YouTube. The new imovie 11 has a great compression to YiouTube built in, and software "mpeg streamclip" is also good.
Might also get better quality using the 60fps mode. Admittedly a lower size but you can then slow it down to half speed and get really good quality and see more of the map. But again that might not be the widest angle. be worth a try.