at the sale price, this light was a great addition to my commuting bits and necessary the times I worked past dark or left in the dark when the days were especially short. it's the absolute brightest light i ever had in either headlamp, flashlight, and even work lamps. and the side lights probably will catch some drivers attention, and they look cool. however there is no flashing mode, which most definitely needed when commuting in traffic. the only way some drivers were able to see me was the existence of heavy duty flashing, which my former Cygolight 350 did extremely well with 2 flashing modes (fast/slow). at the brightest, every driver knew to look out for something. this light has just a dimmer setting where the light literally dims-brightens-dims but it's barely distinguishable while moving at speed.
the other peeve of this lamp is the strap. i have 4 bikes in the commuter rotation and the thing is impossible for my 54 yo fingers to remove and reattach. i am bewildered that no other reviewers noted this. AND - if using a Salsa bar (thicker) with Salsa cork bar wrap, you will be affixing to the very last notch, meaning you have literally no strap left to grab onto when trying to remove it. you have to pinch at it, and it was so stiff, i though of using a wrench...seriously. if not for the fact my Cygolight had stopped holding a charge (after just a year), that alone would be cause for return as i am often deciding in a matter of seconds which bike to take and don't have 5 minutes to mess with removing and installing a light before heading out.
the only thing that saves this fact is the light swivels 360 degrees on the strap and you can get a better angle to grab. BUT it also swivels while you're riding so the light basically goes left and right of where you need it constantly. this is such a ridiculous discovery and there is no way to keep it pointing where you want as every bump causes it to move. the only relief is one side i have my bell mounted and so it only can swivel so far. this is a major fail for me in dark commute.
I did not try the helmet attachmentbut thanks L&M, nice add, but I'd rather you saved money on that and the bulletproof packaging and directions sans words.
the only other critique is weight. YES it is it the brightest, but it weighs in with enough heft to feel like an infant dumbbell. like heavy. not kidding. like, if installed near a bar end it could artificially steer the bars to that side.
lastly, the charger cover would not stay put and eventually flung off when the thing moved causing the flapping cover to catch under my bell then be torn off when i tried rotating the lamp to point back onto the road.
as for charging, it will charge fast, meaning 10-30 minutes, but i found that green light fast charge means 10-15 minutes use time. it needs several hours solid charging after battery discharge and if you keep it plugged in at both the destination and home, it won't fail. i found that use of other micro USB chargers did not adequately charge as well as the OEM.
with so many caveats, i honestly can't recommend it, even if it had a flashing feature, i don't know if i could overlook the major fails. i'll report back should my opinion change, but as of now, i'm saving for another cygolite and this will be the woods and night riding lamp.