You are “supposed” to use the BUIS system that “you” like the best. Don’t get wrapped up in cosmetics, get dialed into function and quality.
I like both the Troy and KAC BUIS. I prefer the 200-600 KAC if running a scope and the Troy for a RDS rig. I don’t have any experience with the micro, but I am sure others will chime in shortly. YMMV…