The KKuK boards are a nice easy answer if you want to fly a cheap "keep it in the car" multirotor. The board works well, but is not perfect, as the gyros are cheap,and you do get drift during the flight. but its no biggie, and for $100 USD its a easy way to get a quad/Y4/Y6/Hex flying. the tuning is simple (3 gain pots) and reversing gyros etc is also simple. Minsoo Kims software versions are leading the pack as he gives you three flight modes , normal where roll/pitch is at 50%, acro where they are ramped up, and UFO where the YAW response is amped up.
From setup to flying is maybe 5 minutes ? (8 if you also have a coffee to drink)
At our little hover-in 6 ran the Blue Board (minsoos KKuK ) and one ran a FY21 (i think)