The control ring is intuitive and the range of output is astounding. The lowest output is low enough it doesn't ruin your night vision, and the highest setting can easily light up a large room or stop a dog attack (confirmed on my first night of use).
The holster was disappointing, as the Velcro closure is positioned for use with the AA extension. If you're handy with a needle and thread you can move the velcro down an inch for use with 123s.