This was literally my first time using it. I wanted to clear Hamburger Hill but the turret I was using before got blown up after I hacked it as an Infiltrator, so I said eh, what the hell. These are the results: :]
*sarcasm on* Sooo OP, they'll surely nerf this. They didn't stand a chance OMG OP OP OP. Just wait and see, one month from now it'll be nerfed ! OP ! *sarcasm off* On a more serious note, you can see how, even with the element of surprise and shooting from behind, your results were far from impressive and you died very quickly once they spotted you. Still, with the addition of the new ES rocket launchers, I think a look at vehicle survivability is needed as they die far too fast in general now.
Individually, the AV turret can be better than individual HA with a launcher. However, a group of annahilator HA supported by 1 or 2 engineers and medics is better at countering vehiclespam than same number of engineers with AV turrets. Overall, Heavy assaults scale better with numbers than Engineers. It's an amazing siege weapon, but that's about it.
But it's better than the peashooter we had before! and imagine a group of Heavies with Annihilators and two Engis with these.
They'd probably still be better having another two annihilators instead (well 1 if you need someone to drop an ammo pack )