GSP speaks the truth.
Tim Kennedy said some stuff when he first joined the UFC, but then he did a 180 almost immediately, no doubt under pressure from the people upstairs.
Christmas Volkmann used to praise the UFC when he was there, and then suddenly opened up about how unfair it was, once he was cut.
Jon Fitch also said very little (besides that he deserved a title shot rematch) but then he had a lot to say once he was released.
Wand spoke of how great it was to be in the UFC and how great Dana was, and after he got busted, the situation got ugly really fast.
Rampage has gone back and forth depending on whether he needs the UFC or not.
The only guys who can be totally honest are the guys who don't need the UFC, guys like GSP, Randy Couture, Tito, and Fedor.
Anderson and BJ have also said some critical things and gotten away with it.
But even a great champ like Aldo is getting thrown under the bus these days, and he's STILL the champ!