I have been reporting from Raiders OTA's about how good Amari Cooper looks, saying on several occasions he has come as advertised. That advertising being that he is a supremely polished route runner who can shake his defender and is lethal with the ball in his hands. That was his MO coming out of Alabama and the reason the Raiders made him their pick at fourth overall.
Now, I suppose just to drive that point home, Adam Caplan reports that team sources are gushing about the work Cooper has done in OTA's.