Since last fall’s arrival of Light & Motion’s Vis 180 and the subsequent arrival of Exposure’s Flare, I have been swapping between the two lights, which each represent a different take a new breed of self-contained, high-powered, rechargeable bicycle tail lights. Bright enough to be seen in all conditions (but no, not bright enough to “blind” anyone except those foolish enough to put it against their eye) and convenient to use, mount, and unmount, both lights have proved themselves- though for different riders. Here’s my take on the Vis 180:
While the claimed 35 Lumen output doesn’t sound much when compared to 900+ Lumen headlights, Light & Motion are notoriously rigorous when it comes to quantify their lights’ actual (rather than theoretical) output, meaning that 35 means 35. Coming from one main red LED and a single side/back-facing amber LED, this output is still nine times as bright as Planet Bike’s venerable Superflash tail light. Though not quite as bright as a car tail light’s 250 lumen, that’s a whole lot of light for a bicycle. Pulsing (rather than flashing), the Vis 180 is visibly different from anything else on the road.
Bright enough to be seen not only at dusk but during the day as well, the Vis 180 is a huge confidence booster. Light & Motion claim that the Vis’s pulse is less likely than a flash to hypnotize drivers and draw them toward cyclists- while still attracting more attention (and lasting longer) and than a solid red light and distinguishing itself from automobile tail lights. Though that seems counterintuitive (think about emergency vehicles’ chosen pattern), the pulse is certainly comes across as friendlier than an aggressive strobe. The beam itself is more focused than some, so relatively little light escapes the horizontal plane, making the Vis 180 seem brighter still than its output would suggest.
The brown anodized aluminum enclosure is reassuringly solid and features a locking mount angle adjustment for the included bracket, which also serves to lock the light to bags’ blinky tabs- important when shelling out $100 for a tail light. The large on/off switch is easy to find but surprisingly difficult for me to use with even thin gloves- a more prominent bump and longer-throw switch would ease that nit. Since my initial review, Light & Motion have begun shipping the Vis 180 with the required Micro USB cable (an Initial Review complaint). 
Also since my initial review, the seals have been upgraded to meet IP67 standards, which means that the Vis 180 should be not only dust tight, but also submersible in 1m of water for 30 minutes. This is a good thing, as early samples (mine included) could (and did) leak (and die).
Thankfully covered by a lifetime warranty, the original Vis 180’s replacement has been subjected to far more rain than the first and has shown no symptoms of ingress. The pictographic instructions included aren’t great (I still can’t tell if the light is charged or charging based on the blinking indicator). Edit: Light & Motion have been in touch to let us know that the full manual is available online here. I would also still like to see a more stable strap on the seatpost mount- the current mount is easy to use but rotates around the seatpost during normal bike handling and switch use. Though I prefer the seatpost mount myself, a higher mount would keep the Vis 180 from bouncing around as much when mounted to bags’ blinky tabs. 
The light’s size (slightly bigger than a Planet Bike Superflash) with a long seatpost mount) does preclude mounting on smaller bikes with saddle bags- something for shorter riders to keep in mind.
Ultimately, the fact that Light & Motion have kept most of the Vis 180’s output in a single plane means that light goes where it’s needed- easily making it the brightest self-contained tail light I’ve come across. The 4hr run time can go by fairly quickly, but there is a medium setting that doubles the time needed between charges and the light does drop down to an amber-only flash mode before dying altogether. For anyone who is good about charging and can stretch to the $100 price, the Vis 180 would be my recommendation. Nothing else has made me feel as confident around New Mexico’s notoriously inattentive drivers.
marc
