It's really awesome in warzones, because you can use it while moving and it DOTs enemies for a long time. This means a single person defending a node can DOT a whole zerg, preventing them from being able to cap b/c of the DOT, even after the defender is dead. Also, unlike Gunnery, AS can melee kite really well. Keep Incendiary and Plastique on the target, spam our snaring/DOT hammer shot between High Impact Bolts, and you can kite around a melee in the 5-10 meter zone so they cant hit you and cant leap to you.
For stationary/PvE DPS though, AS is about the HIB procs you get from charged bolts and full auto. Incendiary isn't our main DD. It just sets it up. Unlike Gunnery, the AS spec and abilities aren't as immediate or simple in gratification. Incendiary alone isn't impressive DD and the cost seems high, but it pays off from the DD and ammo you get from more frequent HIBs. HIB is free on procs, and even gives ammo, so it balances out.