I like Holden and I am surprised he wasn't drafted. The more video I watch of him the more I think he was overlooked in the draft. But we do not know what his interviews were like so maybe it is something about his personality.
At the same time, I see him as another Flournoy type receiver, only Flournoy ran a 4.44 at the combine. But Flournoy, at 6'1", 202 lbs. seems to run good routes to get himself open and showed he can do it against a couple of starting CBs in pre-season last year. I think Flournoy, Mingo, and Holden are all fighting for the same spot on the roster. Mingo clearly has the upper hand only because of the investment. Flournoy and Holden will have to do something really special to win a spot on this roster.