Sony has been competing with their Actioncams. It's a superior product in terms of image quality (according to reviews), and that wrist screen they offer with it is very cool.
There are several solid action cams out there now. A quick search of YouTube shows countless reviews and comparisons. In my hobby of RC aircraft, the ~$80 Mobius cam is a very popular alternative to the GoPro. Most reviewers compare its video quality to that of the previous generation GoPro Hero 2, but it's smaller and much cheaper. Its firmware also supports it being used as a dashcam.
Their waterproof case is junk and the colors are skewed heavy on the blue side.
Still, they're great cameras and I think they look beautiful, but you can see lots of shots of skies and pools that are very unnaturally blue on the Sony models.
If you need something submersible, it's not a good option though.
The first-gen action camera waterproof case was rated for greater depth. I used it in water a couple of times and didn't have any issues. It does feel like you might need to replace it every year if you use it in water a lot (and you have to use a sheet of desiccant to deal with fogging) but it works.
http://buymobius.com/collections/mobius-cameras/products/108...
http://www.amazon.com/Mobius-Action-Camera-1080P-Sports/dp/B...