Main problem can be vignetting like Vid said. The outer corners get fookered up a bit. But the right lens camera selection should handle it fine. We use wide angle lenses on our HV-10s for POV stuff. Reason being say you are shooting a HJ or BJ scene and doing pov. Unless you are really tall you would have to hold the camera a few feet above your head in order to catch all the action properly. With the wide angle lenses we dont have that problem at all. For the HV-10s we use
http://raynox.co.jp/english/video/hd5000pro/index.htm raynox HD-5050 designed for HD video. Loss of quality is undetectable at least on a web format from my tests.