Having used Light and Motion Seca 400, 800 and 1400, I picked up a serfas 1500 and used it for about a week. It's significantly heavier, the beam pattern is inferior (not nearly as wide, not as bright nor concentrated), the unit is much heavier (even when compared to using the L&M 6 cell battery) and securing the battery is not as easy (given its shape). With the seca 1400 being available for anywhere from 199 to 250 these days, this light just doesn't cut it, especially when there's also a seca 1700 & 2000 now. I ended up selling it and sticking w/ my L & M headlights.
FYI, as BRAD is saying I'm a L&M rep, I am NOT, I do not work in the industry. Wondering if Brad works for backcounty?