Its a no brainer, go with the Surefire. My EDC light is a Surefire M2. That is their top of the line double lithium light, and I love it.
Being that I use my flashlights for offduty and duty use, I put them through almost everything...And I have handled all three lights you suggested, and I'd stick to the Surefire. Long before the Pelican. There is nothing wrong with the Pelican M6, but its overpriced IMHO, and its just not as good. For an EDC light, I personally don't like adjustable beams...I like the solid nice beam of a Surefire. I don't have to worry about having a wide beam when I need a tight beam for self defense or throw.
I'd buy the Surefire G2, and put the rest of the money into a box of batteries ($15 for a dozen lithium 123) and that way you are set. Better yet, get a spares carrier, and buy a dozen batteries, and an extra lamp assembly. Can't beat it.
Of course if you need a clip, go for the E2e, or C2, but those cost more than the G2.
But the M6's beam, IMHO, cannot even be compared to a G2, because the G2 is perfect every single time. period
