I have two Luxos U lights; I think they're great. It puts out tons of light, and it provides a decent trickle charge when the headlight is turned off.
Its main drawback is lack of durability; some folks have broken off the spade wire attachments, or had the wiring board break loose inside after an impact, or just straight broken the plastic housing in an impact. Schmidt's all-metal lights are more durable (but more expensive and no included USB charging).
Personally, I haven't crashed with mine so they're both in great shape.
Its other quirk is the light pattern. The Luxos has a large reflector that puts out a very wide beam. However, this results in some jagged "artifacts" in the beam (cutoffs, and bright/dark spots), usually out on the sides. The center/top area is very bright, and should be focused on the trail about 100' ahead. If you do that, then the huge beam covers both sides of the path and beyond. It's an exceptional field of light, compared to the round reflectors on most battery lights. A high mounting position (above the wheel, or on the handlebar) gets you the most of this huge field of light.
MOUNTING:
It comes with the
shaped wire hanger required to mount the light to the brake bolt at the fork crown, and permit the brake cable to pass through.
You can use the same mount to put the light on the front of a rack, as I did on my Rivendell.
Or, you can use
this mount to put the light up on the handlebars, like I did on my Foundry Auger.
Or, you can mount the light to just about any horizontal bolt on your bike (like, on the fork leg or the side of a front rack)
using something like this. Many folks have created their own by using one of the arms from a vintage Weinmann centerpull brake, hence the "Wingmann" name of the Soma product.
TAIL LIGHT:
You can use any dynamo tail light with the Luxos U -- except for Supernova taillights; they use a different wiring system.
If you're mounting it to a rear rack, I really like the B&M Toplight Line Brake Plus, the first one listed on
Peter White's page.
Or, the B&M Secula Plus can be mounted to a fender, seatstay, or seatpost.
WIRING:
Your headlight will come with the wires required to connect it to your dynamo hub.
However, dynamo tail lights DO NOT come with any wires; you have to buy those separately. Peter White sells wires in three lengths, with the required connectors already crimped on.
Or, you can buy the connectors and wire yourself. The wire is nothing special, but the connectors are smaller (2.8 mm) than you'll normally find at your local hardware store.
Many people just use multiple zip ties to attach the wire up the fork leg to the light, and then along the frame back to the tail light. It's customary to run the tail light wire along the down tube, then up the inside of your fender or along the chainstay and then up a leg of your rack.
I've had great success gluing the wires to the frame with Shoe-Goo adhesive. I attached it with lots of zip ties at first, and then cut them off after the adhesive had dried. Shoe-Goo works great because it sticks well to both painted/powdercoated metal and to the wires, and it's easily cleaned up by pilling it up with your fingertip when you want to remove it. It leaves no marks.
If you have a metal fender with a rolled edge (like Berthoud or Honjo), you can tuck the wire into that edge. Other folks use aluminum tape (for furnace ductwork) to stick it to the inside of the fender.