I don't often play fighting games or play with arcade sticks, but recently I have been playing GGX2#Reload, BBCF, Vanguard Princess, and DOA5 on pc with the carbon.
In both GGX2 and BBCF, I have found combos to be easily exucuted with the qanba. Haven't experienced drops. Initially, it was difficult executing an instant air dash in GG and BB, but after finding a good hand placement IAD's were a bit more consistent.
The stick does take some getting used to. Initially, it felt a soft. However, after many uses, inputs are becoming much more consistent.
The buttons on the qanba I've found to be just right for me. There is one button on the top left that jiggles and feels like it will soon fall inside the housing. Additionally, the top left button feels mushy.
The detachable anchors/claw are solid. It's nice not having anything on my lap after long hours.
Overall, I would say the stick is great for the price.