I've had mine for about a week now and I've used it on a couple of night rides.
Firstly the *free* rear light is pretty good but the bracket is awful. I've swapped mine onto a different one which is much more secure.
The front light is impressive and for the price is exceptional. I did have to modify the battery holder slightly due to an excess of springs.
For it's maiden voyage, I used the light on it's own attached using the great little bar mount. It was only about 8 miles down several pitch black country lanes, where the beam although very narrow was more than usable at fairly a fairly fast pace. The lens gives a very bright 'hot spot' and a dimmer 'halo'. The light throws a good distance, but the narrow beam is problematic when cornering as it's attached to the bar and the uneven beam pattern means that it appears even darker outside the illuminated area
For my second ride, I thought I'd mount it to my helmet as a secondary light and the overcome the shortcomings of the narrow beam.
The light was ingeniously attached using a Crud Catcher bungee and a small piece of shaped foam. Very neat it is too even if I do say so myself...
Along with my bar mounted Exposure Maxx-D, the helmet mounted light proved a great addition. Although my bar light has a very even, wide and not to mention very bright beam pattern, it was still possible to make out the light source from the helmet light within it. It is really quite bright enough.
The bar light really became useful on tight turns where you need light where you look. Normally I use a Petzl Tikka light on my helmet, but this new one from eBay is much brighter and more useful at speed. The Petzl is mainly used for climbing and fixing punctures, and I'll probably stick with that set up though throughout the forthcoming Winter night riding season. I'll be adding this light too though I reckon.
After about 3 hours on a set of Duracells there appears to be no sign of dimming yet.
So in conclusion, if you haven't already ordered one out of curiosity, then I'd highly recommend getting one or two... or three.