I think it's a good idea - to be honest most people probably aren't bothered about the smaller differences that might be due to camera and location differences, but would like to see a general comparison.
I'm assuming the picture is taken without flash... And it would be good to try and recreate very similar locations. Perhaps if you post something and give us an idea of how dark it is, we can find places that match it fairly well.
How about rear lights as well?
To make it even more useful, a few words on how easy the lights are to transfer between bikes, carry off the bike, operate on the move, reliability etc...