The reason Pitt's On3 rating is a much higher rating than Pitt's 24/7 and Rivals ratings because it rates the Spanish Twins higher. It has Guillermo a 4-star and Jorge a 3-star.
By comparison, neither twin is rated by 24/7 (0 stars each); while Rivals has Jorge as a 3-star and Guillermo as unrated (0 stars).
You are actually looking at the consensus rankings of the recruits from the link, which is the "average" rating from different websites.
If you click each player that committed to us from the link above, On3's rankings of our players are
Jorge Diaz-78 Nationally, 4 star
Dior Johnson-85 Nationally, 4 star
Guillermo Diaz- 91 Nationally, 4 star
Diaz, the 40% 3 point shooter that is 7 feet tall, is actually our highest rated recruit according to On3 and Jamie Shaw. For those that do not know, Shaw used to be the head director of recruiting for rivals.com.
Its not that any of this information is all that important. But this is the first time in Capels career at Pitt he has 4 four stars coming in in the same class, since Hinson was a former 4 star ranked 105th in high school.