Ok, well, I played singles against a 4.5 guy this morning and won 2,3. The Graphite II does everything well... so crisp and solid on all shots. I like stiff frames, but this one is really stiff. I only felt it flex (a little bit) once, and that was on a forehand return that I just crushed. Compare that to the PDR+ which I can feel flex quite often.
I played the two sets and then went back to the PDR+ for a 10-point tiebreaker. The transition between these two frames is amazingly easy. After playing with the Graphite II, the PDR+ felt light and whippy.
Conclusions... while I played well with the Graphite II, I would probably start struggling to keep up against harder-hitting 5.0s. When I switched back to my PDR+, my first thought was that everything just felt more effortless. The bottom line is that there is really no benefit to me playing with such a heavy frame.