One thing that is confusing on their site is the list of "products." I think that they only sell two cameras - the Hero HD and the Hero HD 960. The latter lacks some features like 1080p, 720p at 60fps, and the expansion port that allows for things like the LCD or the battery pac but costs $80 less.
The surf hero, motorsports hero, and helmet hero are all regular Hero HD cameras that come with different mounts. The camera is the same in all of those cases.
The GoPros are great at what they do, but they are not great general purpose video cameras. They are too small for good handholding. The lens doesn't zoom. You have very little control over exposure and none over focus. The audio is very weak. They only have two buttons, so controlling them is a real pain. In short, they make a lousy replacement for a traditional video camera.
Where they excel is in mounted, hands free use. They are waterproof, shock resistant, and tiny. You can get tons of mounts - suction cup mounts, chest mounts, wrist mounts, bike mounts, head straps, sticky mounts for things like helmets. Used like that, they are fun little devices.
The image quality is surprisingly good. A quick search of Vimeo for GoPro shots will bring back a lot of really good looking video. Because of the extreme wide angle, they are prone to flair. Because they are often mounted on things that don't move smoothly, the video often shakes a lot. Hopefully the new video stabilizers in Premiere and Final Cut will help with that.
The LCD panel is nice, but it has drawbacks. Obviously, it uses more power, so it hurts your run time. It also adds depth to the camera, which can interfere with things like the chest strap mount. It also means carrying more shells if you want to be able to use it with or without the LCD panel. You can't use the LCD Panel, the Battery Pac, or the 3D kit at the same time because they all use the same expansion port.