Let me say I doubted it would work, how could a light predict how much you needed to see without a camera or something like that?
What I didn't like: 1. Mount was a little fiddly so had to fit to the bike with my gloves off. 2. The sensor is on a cable, though the guys said there's a wireless one that works as a prototype but wasn't quite ready for production. 3. Â£450 is too much for me
Not sure about: 1. The light stepped up in brightness when I accelerated. A smoother ramp would be nice, but then again, I would want it to be quick. Though I didn't really notice this after 10 minutes.
What I liked: 1. It was bright, really bright! 2. No separate battery 3. Super nice beam, which is bright! 4. Very light and compact compared to the beer can of an Exposure 5. Even though it's not their brightest light, it's bright! 6. Despite the price, it is great value because it is tough and will last for years - when my current cheap Chinese one dies I'm buying Full Beam 7. Despite it's size and brightness (I mentioned that did I?!) it ran for over 3 hours and didn't even warn about a low battery, should get 4 hours riding on a single charge. 8. it's tunable, you can change settings in the light to make it run longer or be brighter at slower speeds. Though I was happy with whatever the setting it was in when I used it. 9. This Speed LED thing makes you a faster rider - the faster you go the further you can see, you then go faster to see more, I wish I had tracked it in Strava. 10. It's bright! Not yellow or blue but a nice white so you can really read the trail.
Like I said, instead of buying cheap rubbish and having it fail on me I'm going to put my money into a UK company that is run by guys that know what mountain bikers need because they come ride their bikes on the demos too (and know a secret trail or 2).
Overall: I'm putting in a couple of extra shifts so I can afford one of these lights. It means I can ride any night on anything I'd ride during the day and probably at the same speed.