I have an opportunity to get this light at a big discount. Since I don't know much about lighting, I'd appreciate any advice.

Intended use is mostly city riding. I'll also use it for gravel rides that occasionally end after dark. My thinking is low power mode will be plenty bright enough for city use and the battery will last long enough on low for Monday through Friday riding. Brighter will be nice to have for those gravel rides. I like the idea of side lights to make me more visible at intersections.