So, I've been thinking a bit more about the FM04+Ti-PD-S vs. LS20, and the more I think about it, the less thrilled I am about the former option. As brucec mentioned above, one of the main advantages of the LS20 is being able to go from low-flood to high-throw in an instant. For me this is a big deal, and fits very well with my EDC needs. So that's the big plus to the LS20 side of the equation. The plus to the FM04+Ti-PD-S side is the HIGH-flood option. There is also a low-throw option, too, but for me that is a very minor plus. The main thing for most people would be the high-flood option, which is not available in the LS20. Again, for me this wouldn't come close to outweighing the instant access to flood or throw that the LS20 provides.
Just some thoughts from my point of view, my usage patterns.