AKA, why you should only sensor scan when you know they're there.
The fact of the matter is that sensor scan is a great debuff/utility power. It can decloak ships for you and allow you to get out of potential ambushes before they happen.
However, it's on a long cooldown timer, and too often people just fire it off to no effect. Sure, once in a blue moon, there happens to be a cloaked ship in range, but generally, those players are too smart to close to that distance until after you've fired off your scan and have to endure the minute+ cooldown time.
So what's the solution? I'm sure there's a lot of them, but there's one in specific I'm here to tell you about: Tractor Beam Repulsors.
This power is awesome, even if you just have the first level of it. Why? It repulses cloaked ships. It doesn't drop their cloak, but if you fire it off and you see a shiny blue beam going to nowhere, there's probably a cloaked guy or two sitting on your tail.
TBR has a much shorter cooldown timer then Sensor Scan, and is a surefire way to detect cloaked vessels in close proximity. It won't get everyone, of course, but it's a great early warning system to pop if you believe you're dealing with cloaked enemies.
Of course timing matters, as always, but as a reliable cloak detection skill, it can be invaluable, allowing you to save your sensor scan or charged particle burst for when you *know* that there's an enemy ship there- no more firing blindly.
Oh, sure, cannons are much more effective at close range- but given their limited arc, I'd rather be able to do any damage, then to do no damage because there's three BoPs sitting behind me with tractor beams on me.
TBR also gives you room to maneuver, and it's useful 'cause you can use it to 'juggle' a light enough enemy and push him into a corner away from his buddies.
I use it on Ker'rat against cubes when PVP's dead.