It's been a while so I pulled the Streamlight Sidewinder off the vest to check the batteries; while they do have years left on their supposed shelf-life, I'll be dropping some new lithium AA's in before returning it to a kit. Unlike the ACR beacons, the Streamlight Sidewinder is not an omnidirectional beam but is more like a typical LED flashlight beam -- spot with a corona. The strobe is no brighter and is approx 50% on - 50% off, so the strobe should give more runtime than flashlight mode but with the same intensity.

All things considered, I may roll the Sidewinder to another kit and look for an ACR unit like Montanero's MS-2000 or hikermor's Firefly 3 -- the omnidirectional coverage seems a better fit for the role this light plays. The local boat supply place carries the ACR Firefly 3.