Yes, not 100% a fair comparison as my USO day included a late start (stupid hotel check in), 2 hour Hagrids wait, an hour at Mythos, probably an hourish+ exploring the HP lands.
Still even at 30 rides for $250 (you said re-rides) is ~$8 per ride. If G+ is $30, only 4 rides puts you at a better "value" of $ per ride.
Both parks are super expensive, but to me G+ still gives the better "value" over express pass. However, I can totally see how someone has a different opinion than me. I will probably never visit Disney without G+ or USO without staying at a deluxe resort (no way I am forking over $700+ straight up for express for my family of 3).