Hello Mark,

I own 3 BD Storms and I also own the BD Cosmo.

I chose the storm because:
I wanted a high output when needed but the ability to dial it down when not.
It is more water resistant (gasketed battery case) than most if out in the rain or around water and clumsy :-)
It is both regulated when the batteries are fresh for a consistent output and then it drops to unregulated when the batteries are running low. The high lumen numbers on any headlight are for brand new batteries. After 30 minutes the total drops down in any headlight. Regulated lights keep a higher output longer but they drain quicker than non regulated.
I like and use the red led feature frequently.
I wanted a strobe if I needed to signal the calvary.

I like it a lot and bought more so I could keep 1 for my bob, 1 for edc and 1 in my hiking backpack. The edc light gets used while camping / hiking and the other is backup.

I have frequently used my edc storm in place of a flashlight. It uses 4 aaa for a longer burntime but it is not heavy on my head.

The only thing I don't like is that my edc storm has developed two hairline cracks on each side by the secondary leds. To be fair it is tossed in a bag and used all the time.

The cosmo was on sale for a price too good to pass up. It is nice but less powerful and not as water resistant. It is my edc backup and would definitely work well if my storm broke.

I would recommend carrying lithium batteries. It gives a definitely longer burn time and it makes the unit much lighter. I keep alkaline batteries in the unit for the more constant use and switch to Li when I use it in the woods.

If you chose something different please let us know what and why. I'm always interested in a good light.