The biggest advantage I found to being PPRO was not the upgrades (I'd guess I got it about 40% of the time), it was the same day flight change. I used that a lot.
- The same day flight change is nice when it is available, Few times I tried as EXP I didn't get it. By the way, my wife was just told that the same day confirmed flight change is unavailable for EXP traveling on MilesAAver.