I've been looking for a headlight with a full cutoff beam for years. They're required by law in Germany and a few other countries. Most of those that are imported are intended for dyno setups though and I'm not really interested in doing that much work on multiple bikes, and I don't consider charging batteries to be a big deal.
I've been watching the market - last year I very nearly ordered an Ixon IQ but I felt it was still not quite as bright as I would like for the type of roads I ride on (sometimes really not great). Finally this year they upgraded the LED and I thought it was worth ordering, so here it is - purchased from a German eBay vendor: the B&M Ixon Core IQ2-50.
It's pretty cute and tiny. At 50 lux, it's not as bright as my bigger (500 lumen) headlights, but it produces a very high quality beam that makes better use of the light that it does put out, and the cutoff is quite sharp so oncoming drivers should not be uncomfortable.
In case you care, here's the packaging and included stuff:
For the beamshots in this article, I put the camera in manual mode, attempting to get a setting that I thought reflected what the light looked like in real life. I wound up at ISO 3200, F/3.3, 1/8 sec.
Here's the light on high beam in my driveway. The far end of the beam is probably about 50 feet away.
For comparison, here's my MagicShine light, which is rated at 800 lumens but is in reality probably something like 450:
This seems great, but the very hot center tends to cause your eyes to miss stuff that's not as well lit, so I think the flat pattern of the IQ2 is likely to be about equivalent for spotting potholes and other obstacles. Also, since the beam is unshaped, you should realize that as much light as is hitting the ground just outside that hot spot is the same amount of light hitting an oncoming driver's eyes.
Here's a garage door shot showing the cutoff of the optics:
I have not ridden with this light yet, I will update in a few days when I've commuted to work with it.
The light is rated at a bit over 3 hours on high, 12 hours on low.
The light does not have any flashing modes, since flashing front lights are illegal in Germany.
I very much like the light switch - 2 second hold for on/off, press once to switch high/low. Having to click through strobe and then off to get back to high beam from low in pitch black conditions is irritating.
The button has a blue light for high, red indicates the light is on low. The button blinks between 1 and 5 times to indicate current battery condition - it does this 3 times in a row, then stays on for 2 minutes, then does it again (or it also does it again right after being switched high/low beam).
The light has a built in LiIon battery (non-changeable) and charges from a MicroUSB connector. It ships with a USB cable and a USB charger, though this has an EU AC connector on it so you'll probably just have to use your own if you're in the US.
Here's a closeup of the optics in case you dig that sort of thing: