We looked at Fenix’s first headlamp, the HP10 recently, which was a high output unit with a relatively heavy battery pack on the back of the unit. The Fenix HL20 was the company’s second headlamp and went in a different design direction. The HL20 has just one button used to switch modes and turn the light on and off, is powered by a single AA battery, and does not have the extra bulk and weight of a battery pack meant for the back of the head. The single battery means that the light has lower output and shorter battery life compared to the HP10, so there are some trade offs when going with the smaller unit.
The HL20 would make a nice headlamp for anyone looking for a general purpose light. It doesn’t have huge output or crazy battery life, but it does have decent levels of both compared to most of the other headlamps on the market. You could definitely do worse.