I added the fixed light mount so I could use a top cap Garmin mount to run my Varia radar light with no obstructions.
It works great and is very secure even on gravel and moderate single track.
I tend to gauge products based on its usefulness, price and expected lifespan. I’ve purchased the entire kit: carbon rack, UD22 Panniers and AP20 top bag; I’d purchase them all again without question!
Paired with a 3D printed garmin mount to fix my radar - ideal!