I'll start this off with FREE

because when I played P2P games I felt almost obligated to get my game time in because I had payed for it ....... with F2P games I buy what I want when I want and if I don't play for a few weeks, who cares because its not wasting my subscription time.

Arguably you do ironically tend to pay more for F2P than you do P2P but you can also go months of playing without dropping dime into it, which means when times get tight and you can't afford to deposit which has happened here and there it isn't cancel your account and suck up not playing your favorite game because you can keep right on trucking in your favorite F2P.

And with lots of P2P adopting a mutant subscription fee + a cash shop ..... I can say there is no way I'd go back to them on principle alone.