I think the take on this will be pretty subjective and vary greatly. Especially when it comes to feel where everyone is different. I love the last generation APD (2013) and felt it was the best combination of power, spin, control and comfort in all APDs. It wasn't as raw feeling as the APDO, and I liked the somewhat muted feedback. Also left a bit room for customization if one wanted to go that route. The APDO was a little too lively for my taste and without modifying it buzzed a lot. Also did not feel as refined to me. For me, hands down the last generation APD wins.
Among all 4 generations of APD, it is also the most comfortable to play with, in my experience at least. Mine are 67 RA strung (measured on RDC), same as the APDO RA rating. Have never had any arm issues whatsoever and I have had them since forever. I love trying different racquets, strings and gear but find myself coming back to them in the end one way or the other.
Of all the 4 generations Aeropro Drives, for me the worst one was in fact the APDC, the one that came after the Original and before the 2010 GT. Hollow feeling, had a very pronounced tinny and pingy feedback, and lacked the solid feedback on ball contact. They upped the swingweight with GT version after that and then lowered it back down with the APD 2013 (before upping it again with introduction of Pure Aero in 2016). I think a lot of folk like the 2010 GT too because it swung heaviest and felt very solid.