I have hit with the last three generations of PDs and here is my opinion
PD Cortex: the most lively of the three with the most raw feel. IMO the most powerful of the 3 gens.
PD GT: the most muted of the 3 with the least feel (overall I hated this generation, with exception of the PJ)
PD 2012: overall my favorite PD yet. Stock weight is a great base for customization, feel is lively enough to give decent feel, yet muted enough to be easy on the arm (relatively considering the stiffness) without making the racket feel numb