The current state of Quad AA is not very fun, for a couple of reasons:
1. The camera shake when firing is annoying; combine the shake with the hard-to-predict dodging of the enemy Mantas and the lack of feedback on if you are hitting or not, and it's just not as satisfying or fun an experience shooting those guys down as it could be. I'll just let the AI do it (after moving the unit into the right spot), when at just about everything else I'm substantially better at killing than the AI. If the idea is to make players shoot bursts, perhaps a faster overheat or only adding the camera shake after an extended burst would be better.
2. The fact that the guns *almost* traverse down low enough to engage enemy ground units is weak. It's a lot of fun to use on ground units but I hate having to find a good spot on the terrain to angle the guns down that extra 10 degrees that allows me to annihilate them. If these guns are designed to NOT be allowed to engage ground units at all, there are better solutions: make the rounds only good against air units (no AP capabilities), turn them into something that requires locking on to an aircraft to fire, or something else that isn't just a mild frustration to using them but rather outright denies the ability. As it is, I'll ALWAYS be tempted to roll it ashore and park it on a hill to get them to come to me, as it's one of the few starting ground units I have that's capable against both ground AND air threats (and I don't like waiting for the AI to catch up to me when I go driving, hehe).