Trying to decide which cam to buy, I narrowed it down to the Sony hdr as100 but like everything else the deeper i read into them the more confused I get. I will be using it in clear rivers mostly above and underwater. Any help would be appreciated. Thanks

You've made a good choice. That Sony model should work great.

I use a Contour ROAM. I'd probably go with a different model if I had to do it over again.