Not much of anything.
Toed out gives you slightly better handling and stability in the turns at speed. And I do mean slightly. It will also give you more stability when hill climbing. The tires will try and pull straight when it 4X going up a hill.
Toe has nothing to do with darting. You want to feel darting go - castor.

IIRC my quad was set a 1.5" toe out. The steering was really heavy. I set it to 1/8 toe out and now the steering is nice. I never looked back.