Yes, EMP destroys anything electronic - including killstreaks. This is the reason why I prefer not to equip anything that can be shot down, because it feels like a waste. I didn't realize adv. UAV could be shot down, so I'll probably change my setup to SAM, Stealth and EMP.
Yeah, EMP owns. It destroys all enemy killstreaks. Prevents them from putting up more while it's on. Kills their radar like a counter UAV. Kills their RDS, and all their equipment too I believe. They can't even see the scoreboard.
People love the osprey drop cause it's full of goodies. I hold my EMP just waiting to ruin their Xmas.