I can never justify buying an aep when the galaxy mp5ks are so cheap and probably will work better for a sidearm role.
Except its not a sidearm....
Pros: Extremely quiet, very reliable, work in any temperature, lower cost than gas pistols.
Cons: Limited parts availability, not as "fun" as a GBB, limited power output.
Right now, I'm sitting on 7+ G18's, 2 MP7's, 2 Skorp's, 2 M93's, a Mac-10, and a partridge in a pair tree. I'd take them over a Galaxy MP5k any day.