I was seriously considering the Fenix L2D and it's replacement the LD20, but 4Sevens has now come out with it's Quark line and the Quark AA^2. The reviews out there have them as competitors, with Quark slightly coming out ahead in part to due it's moon feature outputting at less than one lumen, while L2D/LD20 using 9 lumens (battery savings). The max lumens of the Quark AA^2 is only 10 (170) less than the L2D/LD20 (180), which might be insignificant under real world settings. They've also got a couple of programmable features.
I would mainly use this light for ride in suburbs, where there are street lights, but are significant gaps in between them where a light would be good. I'm wondering if anyone has had a chance to use them on their bikes yet.