Anything above 7 isn't an advantage
Too sensitive for long range AR and close combat SMG fire
Around 5-8 is probably the most benificial for competitive.
Any higher for trick shotting
Any lower for first timers
Playing on 5 right now but might bump it up to 6 or 7. I used to be a 10 sensitivity player (14 now) but when you start getting into the competitive scene you'll notice people play on lower sensitivities because accuracy is everything...okay not everything but it's really important to being a good player.