I'm playing in a local tournament here and I agree with the OP. Seeing a bunch of Mens 3.0 singles matches in progress at the same time, was both beautiful and ugly. Some people hit beautiful winners, and then turned around and lost their own service game @ love-40.
Some people were jumping around like lunatics, wasting a lot of energy, when all they had to do was retreat by a couple of steps to cover the majority of the court.
Others had this wonderful 80-90 mph+ first serve that they so spectacularly displayed during warmups. But by the time of the end of the second set, they were patty caking it over the net.
meanwhile, the 3.5's seemed to have their stuff together. They didn't patty cake it. They all maintained fast first serves. They had long rallies, no moon balling. Plenty of top spin, good placement. I couldn't really find anything wrong with their play... and its no wonder that quite a few of the 3.5's that also signed up for the 4.0 draw won in the initial round of 32, beating other 4.0s.