Apple is considered to be one of the top cornerbacks in the 2016 draft class. At 6'1" and 199 pounds, Apple has good size and at the NFL combine, he ran a 4.40 40-yard dash. Matt Bowen, an ESPN NFL writer and former safety, described Apple well.
As noted by Bowen, Apple's biggest weakness is that he sometimes struggles to find the ball in the air. That is something that can be fixed with good coaching. Interesting enough, this was the biggest knock on Ronald Darby, Buffalo's second round pick in 2015. After Darby's rookie season, no one would list locating the ball as a weakness for Darby.
Drafting a cornerback in round one may not be a popular choice, but a player like Apple would certainly bolster Buffalo's secondary.