This is the latest, at least that I know of, from Streamlight's Rail Mount series and I've had mine in for a couple months now... my thoughts:

Pros:
-Cost. Comes in at around ~$115 shipped street price
-0 flickering issues or anything like that
-Can be programmed to 3 different mode functions (I suppose this could be a con as well)
-fits on any Surefire Scout mount that I know of
-has helicoils in the mount which are going to increase durability over just standard threading
-1,000 lumen / 27,600 candela output
-comes with a tape switch / tape switch mount
-beam pattern has a lot of throw (could also be a con for some) as shown in the video

Cons:
-made in China
-somewhat heavy vs. some competitive options at 6.4oz

Full review with beam comparisons and other ramblings I add in: