I've also got a Microstream and really like it. I got the version that comes on high first (bronze color) and love how it fits in my pocket. The clip hasn't moved since I started using it. While it's not enough for "major searches", it's fine for use with a pistol in the dark the way you'd use any other light. I've even used the clip on my hat brim so I could see to lube the chain on my bike the night before a pre-sunrise bike ride.
I've got a Sidekick. It's fine for use as a light by itself but too awkward to use to illuminate something with a pistol in your other hand, especially if you have your keys dangling off it.