I run the Firefly with a Metz 50 AF 1. The battery is more than made up, mostly you have to control the power even down. The images are depending on the distance, soft and well-directed lighting. Excellent to put as striplight of erotic photography a - as often as Strip Light - but also ideally suited for part-body or portrait shots.
Conclusion: The company Aurora delivers the Firefly a high quality, solid, light shapers for Aufsteckblitze. 100% satisfied, even if the operating instructions for the FBO 65 was there. However, explained everything really saying without thinking about it :-)