Items such as blaster, rocket, sniper have a % miss chance against you when aim scrambler is active.
This is only half the story as the miss chance is always present without an active Aim Scram but at a lower rate of course.
In theory the aim scram should just increase the chance to not get hit but by weapons like Blaster; Rocket; Sniper Blaster and even Sticky Bomb (yes it is possible that a Sniper blaster and a Sticky Bomb can miss a unit that has active aim scram).
In practise against AI enemies it fails most of the time to do what it should do even if it has the same or higher lvl tech then the enemies. Some players even say that with an active Aim Scram they get hit more often then without it
On the other hand Aim Scram does not work against Thermo Blast; Mines; Aggro Bomb; Oribtal Strike; Lightning Chain (as least never enocuntered a miss with this one) and Deflection Droid
From what i know and have encoutnered it works decent enough in PvP while it lacks massive efficiency in PvE scenarios.