Shrike9, hello Brother.
Here is my experience:
SF E1 is the best light to clip to your helmet, you will need a M15 mount/clip with it. E1 is a LOT brighter then any Streamlight or Pelican and about third the size anf weight of AA Maglite. It is very water resistant, I had it in the rain for hours at the time with no problems.I got a new hat now, and M15 doesn't fit, so I sold it.
In my pocket I have SF M2. I put that light through hell-it still works, still the first bulb. I had it at the fire school, in a life burn, about 750F at a chest for 15min. It melted the lens ring a bit, and the light got pretty hot, but worked. I got Glo-Flex wrapped around the bezel, when I have to brake a hydrant, I don't lose it.
If we have power lines down, or any situation I need to look up on power poll, I use SF M4. It is A LOT BRIGHTER then SL Litebox(we have 16 of them),and about third of the size.
The reason I like Lithium power - lithium can take high temps a lot better then any other kind of battery. At 500F-600F any alkiline or rechargeable will blow, while lithium will not, it will jusy overheat and shut off, as soon as it cools down it will be like new. And the shelf lifeis 10 years, so you can leave it in your coat for 2years without any worry, when you pick it up, it will be just as bright.
I have pics of my gear and flashlights on SF board
Picture
There is a pic of SL Litebox vs. SF M4, and my gear with M4 and M2(M2 has Glo-Flex)
Did I mention that SureFire sets the standards on beam quality? You can see what I mean in the pic.
Ultrastinger - NO,NO,NO. The lens will melt, batts will explode, it is not water-proof, and it is way to big.
Syclone - same NO, the light is too weak and too big. Very not handy, size like a 16oz can of bear, no kiddin.
Survivor - those are OK, very good light, but the beam is too tight - which makes it uselless to me. Those Smoke-Cutter bulbs make the beam very tight, and they claim it can penetrate the smoke. Well as a fellow firefighter you know it is a bunch of poop - when you are in the fire, it doesn't matter what light you have - it is useless. Ever put high beams on in the dense fog? Same effect - just reflects right back at you. When you are in a bad one, you are blind- feel the way with hands and look for the GLOW. In the dark and smoke it is a lot easer to see the fire without any lights.
I got a Pelican miniflasher with my PASS, so evrybody can see me(it's a tiny LED flasher).