going over the specs...

HERO & H2 are both f2.8. the HERO claims "high performance in low-light situations" and the HERO2 claims "Fixed Focus".

HD: Light Sensitivity: Super low-light sensitivity (>1.4 V/lux-sec)
H2: Light Sensitivity: .84 V/lux-sec

does this mean that the HD (H1?) is better in low light?

it looks like they changed the images sensor from "1/2.5″ HD CMOS, 2.2µm-sized pixels" to "High Performance, 1/2.3” CMOS Image Sensor", and while it previously supported "5 megapixel" photos, it now supports "11MP, 8MP, 5 MP" photos. if i'm reading between the lines correctly on this (someone please correct me if i'm wrong)... the size of the image sensor is very slightly larger, but the pixel-count is slightly more than doubled and, as a result, the light sensitivity is pretty much cut in half.

if that's the case, it looks like the HD/H1 is still the best pick for a bike-cam at night. not that it's a "night camera" by any stretch, but it does a lot better than the Contour-HD, in low light.

now that there's a new H2, it looks like the HD's street price is about $200(US) for the helmet or motor-sports package.