SB Nation's University of Alabama blog Roll Bama Roll has a nice profile of Jets cornerback Dee Milliner to give you a little extra background on his game and who he is as a person.
It's not a coincidence that Milliner left the others behind. Dee has good size for a cornerback, at 6'0", 201, and with 32" arms. He turned in an excellent 4.37 official time at the Combine, and has a burst that gives him superior closing speed when the ball is in the air. Even better, Milliner almost invariably manages to turn his head and locate the ball, giving him a chance to use that closing speed. He also has the strength to prevent physical receivers from stealing passes. Together, his speed, burst, length and technique constitute the complete package for breaking up passes.
For Milliner's rookie year, it probably would be best to keep expectations low. Sometimes it clicks immediately for a rookie cornerback like it did for Darrelle Revis, but there are a lot of rookie corners who enter the league and get burned on almost every play. That is true even for some players who eventually become really, really good.
The Jets already have incumbent starters in place with Antonio Cromartie and Kyle Wilson. Milliner should be given every chance to earn a starting job, but realistically, he could be the 3 or even the 4. I think the best approach to take is to set expectations low and view anything he can provide as a bonus. If he could somehow outplay Wilson and take a starting job, he might be something special.