Take it from someone who wishes he'd turned it off from the beginning -- TURN IT OFF.
Look at what Murdr said and think about it. Two huge problems come from stall limiter:
1. YOUR airplane will stop turning, banking, nosing down, whatever SOONER than your unlimited opponent. He gets to make tighter turns than you do, so YOU'RE getting handicapped by having stall limiter on.
2. (What I think is even more important) = You don't get the chance to "feel" the limits of your airplane, so you don't learn to ride the edge of control. You don't get to appreciate when you're cutting it close, and when you have more maneuverability than you think. It deprives you of some immersion, but even more it keeps you from feeling things about your plane's capabilities, SO you have a harder time instinctively knowing when you won't be able to cut a corner or get a shot.