If you are like me, you will use the L2 a lot more, or wish you had gotten it if you get the M6. I might order an L2 today (if I can make up my mind /ubbthreads/images/graemlins/smile.gif )
I don't know if the thrill of 250/500 lumens is actually enough to outweigh the utility of the L2. I mean, you don't need to ride a helicopter to get groceries or rent a movie. A car works better.
[Oops. You mean the Pelican M6, don't you.]
Get the L2. I believe Surefire makes a better product. Tougher, more reliable. The reason not to would be length.
Scott