The NFL really isn't loaded with 220 pound WRs who can run 4.40 and jump out of the gym. There are lots of "good" athletes, but that's another level and those guys don't grow on trees. There's almost nobody out there who combines the speed and the size of Moncrief, so he's in rare company.
I don't think Moncrief is one of the best WRs in this class in terms of intangibles and WR skills. He drops too many balls, isn't particularly elusive, and just doesn't seem to have the "it" factor for working in tight spaces and making things happen. However, he's not as bad as people make him out to be. People talk about him like he's some total workout warrior with zero football skills. I don't think that's very accurate. He wasn't a dominant player in college, but he wasn't bad either. 900+ yards each of his final two seasons in something like 13 games. While he isn't consistent, he has at least flashed the ability to do a lot of the "skill" things that a WR needs to do. I've seen him make leaping catches over defenders, catch the ball away from his frame, run crisp routes to get separation, and contort his body to catch poorly thrown balls. He might not be an A+ from a skill standpoint, but he's not an F either. More like a B or B-. When you combine that with his off the charts physical qualities, it will probably be enough to achieve considerable success at the next level.
I said it earlier in this thread, but I doubt that he has the football skill or athletic skill to become a jack-of-all-trades #1 like VJax, Demaryius, or Marshall. However, I think he compares pretty favorably to guys like Torrey Smith and Mike Wallace who have flawed football skills and even flawed physical skills, but have still been able to make a pretty significant impact because they have physical traits that are hard for defenders to cope with. I think Moncrief might even be better than both of those guys in terms of his overall athleticism/skill combo. So while he doesn't warrant the Demaryius comparisons, he could still end up giving you a nice return on your investment for the late 1st-early 2nd round rookie pick he's likely to cost.