Kiper/McShay just get more attention because they're on ESPN. Neither are acknowledged as the "aces" of their profession. Most of the more recent ratings have Claypool in the 70 - 80 range ( maybe of the 10th-13th best wr ) in terms of overall rankings but because of fit and need and how the draft evolves, he could go higher or lower. His initial big attraction is his possible switch to TE (because the TE class is so weak ) but his combine performance showed he has some legitimate top-end wr skills. I still say 2nd half of 2nd round.
By the way, that mock was made nearly a month ago prior to a lot of free agent signings. No matter what Kiper says, I can guarantee you that GB isn't going to pick Claypool in the 1st round because he doesn't fit their need at wr, at least not at that position in the draft, GB needs a slot guy with an emphasis on quickness. GB is loaded with tall receivers, very similar to Claypool. Many more recent mocks from knowledgeable guys have him going as low as early 3rd. As I noted, Boykin had much the same reaction last year when he knocked folks socks off at the combine. Lots of early drafts had him going in the 1st and he ended up at 93.
We'll see where he goes. If you're right, you can dance on my head. I didn't mean to imply that you were making it up.
By the way, if you can't already tell, I love the NFL draft. It is probably my favorite sporting 'event' of the year.