Busch & Müller Lumotec IQ Premium Fly RT Senso Plus
The new Premium Fly is slightly brighter than the regular Fly (60 vs. 50 lux), but the big difference is the width of the beam. The Premium beam is much wider. Not quite as wide as the IQ2 Luxos, but almost as wide. The Fly isn't as bright as the Luxos, but this RT version excels as commuter/city light because the Fly LICHT 24 daytime running lights are more conspicuous than on any other B&M light, with six widely spaced bulbs.
At nighttime, when riding under streetlights the extra width of the Premium beam is mostly drowned out by ambient light, but as soon as you turn onto darkened roads the difference is significant. Here's a heat map of the IQ beam.
And the IQ Premium beam:
The Premium fly model is the RT Senso Plus. The "R" designates both a built in reflector and nearfield lighting, which illuminates the road directly in front of the bicycle, rather than the beam starting a few feet down the road. The Senso mode is a nice "set it and forget it" feature that senses the ambient light conditions. When the sun is out out the LICHT 24 daytime running lights (pictured) will turn on. At dusk the light will automatically switch to the night-time headlight beam. If you want a light with Premium optics without the R optics that throws more light further down the road (making it more suitable for fast descents) I'd choose the Premium Cyo T Senso Plus.