Ok, I've just used my Blaze Laserlight, perhaps in not the best circumstances considering my ride was entirely in wintery rain and darkness, mostly country lanes with a few urbanised streets.
The first thing I noticed about the light is it's weight, it's not light and a little rear heavy, which leads me on to the next point, installing it on the handlebars. Bearing in mind it carries a laser, I took extra care installing it onto my handlebars, I have oversized road handlebars, and the light comes supplied with 3 different sized silicone shims, I used the medium sized one. At this point I aligned the light and tightened the mount that the light sits in and set off. (I also had an RSP RX480 as a backup)
The light itself has two brightness options, 100lumens and 300 lumens + a flashing option, the 100 lumen setting is alleged to be able to run for 4 hours, with only 2 hours for the 300 lumen setting. I found the 100 lumen slightly short of satisfactory, it's enough light for busy sections of the Bristol/Bath cycle path, for example, or a well lit street, but it doesn't illuminate the darkest lanes well, upping the brightness to 300 lumens was a little more confidence inspiring, but being mindful of the 2 hour run limit meant I was keen to reduce the brightness quite quickly.
The laser option projects a green bicycle on the road ahead, I haven't tested this fully, other than verified that it does illuminate and does project a bicycle, the bicycle image can become a little ill defined when riding over rough chipsealed roads as we have in South Gloucestershire, causing the handlebars to buzz, this is also transferred into the laser causing a fuzzy looking bicycle, slowing down reduces the severity of the occurance.
The weather was wet, and it soon became apparent that this light does not like being wet, the buttons became unresponsive after 7km in the wet, I stopped under a bridge to clear my glasses and dry the light, it did become fully functional again once it had dried.
My opinion: I will probably assign this light to the Brompton, since it's designed for urban riding and serves that purpose adequately, it perhaps isn't the best for country lanes or long rides where brightness, reliability and longevity are needed. I was wary of the weight of the light upon installation, a slack installation could easily causing the light to end up pointing up in the air after a few bumps, this isn't something I'd want to see while the laser is in use.