To me, PS offers a significantly better seat with improved pitch, leg room, and there are typically just 2 seats rather than 3 on the sides of the aircraft. As a taller person and one that tends to travel with one companion, this makes for a much better experience on long haul flights. That said, it all comes down to price. $250 upgrade one-way per person is about the maximum I would pay for PS over Delta Comfort/Economy Exit Row seating. And that's assuming I could book two adjacent PS seats on either side of the aircraft.