I like the original APD quite a lot, and like the APDC quite a bit, too. Personally, I don't love the new GT version. But it comes down to flex, and what you like in a frame. The GT is far stiffer than previous versions, and plays quite differently. The Cortex is the "softest" of the bunch.
I picked this one up because it was almost brand new for $40. I put some Gamma live wire xp in it at 57 lbs and if nothing else it's a good backup racquet.
I took a few racquets out for a demo and liked the Pure Drive Cortex the best.
Pure Drive Cortex - Great all around feel and power
Wilson Kobra Team - Too much pop... couldn't hit through
Wilson Kobra Tour - hated it
Prince O3 Black - felt like I was swinging a light saber with all the noise from the o ports or whatever they are called.
Next I want to demo the Pure Drive Roddick GT Plus and the Aeropro Drive GT Plus and see what I think.
Based on what you said I'll try to demo the APD Cortex too.