When playing against Symmetra I find myself killed by the turrets quite often, but when I try to use them to control a space myself I always mis-judge and leave them stranded out-of-range, to be easily picked off. They can notify me that a player is in the area, but never do much damage.
What is the range of the Sentry Turrets spawned by Symmetra? Are they only useful as very close-range traps/sensors, or do they have enough range to control a medium-sized space as well?