I think that's stupid that Ops can take over friendly turrets. I think if I build it, I should be able to take control of it. Like The Wrangler in TF2. I mean I don't mind having an Operative like my bud Drop_Dead taking it over, but I think if he can, since I built it, I should as well.
Yeah, but engineers only have a torch, its the operative with a PDA, you cant control a robot with a torch. It also is another step in the direction of teamplay.
It doesn't seem all that useful either way. Turrets are good because they add another gun to your team. Taking someone out of the fight to control a turret kind of negates the point.
There are lots of advantages to be had. It's a stationary gattling gun with unlimited ammo. You are also able to use it from safety. And you can be more accurate than the turret will be by itself. The turrets track relatively slowly, so a skilled light player can serpentine to avoid getting hit. Turrets also have a maximum targeting range that could be overcome.
All-in-all it seems like an excellent ability for a Heavy Op who intends to stay back and guard against enemy operatives. That way, he can help out the turrets if they are having problems killing a skilled player.