This is an interesting experience.
One thing I have learned is that the capture size and the project size mean a lot.
Capturing 800 x 600 window on a 1920 x 1080 screen does not look so good in any project setting.
Capturing a 1920 x 1080 window and Google Earth Full Screen looks pretty good in a 720p project and even better in a 1080i project.
Have tried the Uncompressed format at 30fps and got pretty good results. I did make changes to the Google Earth options and some of the Camtasia record options.
This has been a very interesting experience so far.