I have a couple of the Pelican M6 lights, and really like them. I think they've got a nice form factor, and are sturdy lights. The switch can be modified to become a click on, click off with momentary on (I'm told this takes some elbow grease - I've been able to buy mine used, with the clickie already installed).

Flashlightlens.com offers the "clickie mod" mechanism - not sure who else might have it.
Pelican clickie

The replacement lamps are cheaper than Surefire's - they're about $5 each at brightguy.com, and I'm sure you can find them elsewhere, too.

Replacement lamps

I've read on Candlepowerforums that the Pelican M6 has slightly better throw than comparable Surefire lights - but I don't have any Surefires to compare it to. Based on the comparisons I've read on CPF, and owning a couple, I'd say the Pelican M6 is a good-value, sturdy light.
My .02
Dave