I think its max activation range is 50 metres, which is a bit long for many pistols but it is pretty good as an early warning system for people sneaking up on you or charging in your direction.
Right but it would be more useful if its 700 dps would focus fire on what you shot. it could default to the alarm system when you are inactive. It also would make spitfire auraxium simpler since you could stop shooting the damaged target to let the turret get the kill.
I use the Spitfire and I get some kills every now and then. The trick is to deploy it and guard it: as it beeps YOU attack, then the turret will help you. If your enemy make the mistake to focus on Spitty you kill him. If he shoots you then you still have the extra firepower. I have this special loadout for defending capture points: Claymores, Spitfire turret, Sticky grenades, Max nanowave, auto shotgun.