Tonight was the first ride with my new lights, and I’m very impressed. By turning them on in "race mode" a quick press of the button flicks the light between high (700 lumens) and low (175 lumens). Low is more than adequate when there are other sources of light such as street lights, and high is just superb when it gets darker. Hopefully they’ll prove to be more reliable than my previous lights.
One downside is that it interferes with my cordless computer and stops it working, hopefully it won’t affect the GPS when I get around to fitting that as a replacement.