I've had good luck with Cygolite products. Hotshot tail light, an older Expilion 250 headlight, and most recently a Dash 450. I rode at night quite a bit, and the Expilion 250 I used as a helmet light. Now that I'm retired and no longer ride at night, I'm using the Expilion on one of my road bikes as a bright blinky, and the Dash 450 serves in that roll on another road bike. I move the Hotshot from bike to bike as needed.

All of my Cygolites have been reliable.