The GoPro is an excellent, relatively inexpensive choice. When you factor in that you can use it elsewhere and reuse it and don't have to develop film, it will fairly quickly make up the difference with multiple reusable cameras. I do not recommend the head strap, as it does interfere with the mask and my cohorts have seen more than one lost off the head, either at the surface on in a current. I used it once and was not happy. It also places the camera close to the bubble stream and you pick up a lot of bubble and regulator noise.
On the other hand, I bought the wrist mount and was extremely pleased. At first glance, it may not be intuitive how the wrist strap could work, especially when sitting at the computer and imagining the sideways positioning of the camera could possibly work. However, when underwater, if you swim with your arms crossed at your chest, the camera points in the perfect direction. Rotating the camera on your wrist is enough to get the perfect framing. You will have to keep in mind that it is on your wrist when signaling your buddy. That may dictate which wrist you put it on or which hand you use to signal.
If you get the GoPro, I would recommend the wrist housing and installing a flat lens solution on that housing. I went with the BlurFix and the red filter they sell. That leaves my other housings stock and I now have a dedicated underwater housing.
Finally, the best thing about the GoPro for me is that it is a set it and forget it piece of equipment. I'm capturing video during my dive, but I'm not impeded in any way and both hands are free.
