While looking for some guidance on a new front light I stumbled upon this useful comparison tool from Road cc.
http://road.cc/lights2012/index-wide.php
You can select two different lights to compare side by side, using a view of a country lane as a backdrop. There is a dividing bar that splits the image in two, showing one of your chosen lights on either side of the bar, but this can be moved to see more of the view from one light or the other.
Hope it helps anyone looking for a new light.
Allan