If you dive into the subscriber-only discussions of prospects on BA, after praising Rudy Owens's fastball command, DK says of him

His secondary offerings, a slurvy breaking ball and a changeup, are no better than average pitches but he locates them well. 

Pirates Prospects Prospect Guide says of Owens, in sharp contrast,

His changeup is possibly the best in the farm system, boarder lining as a plus offering . . .

This goes beyond arguments among scouts. Either Owens has a pretty good change, or he doesn't, and the attributes of a good change are measureable: arm speed and slot, movement, and speed differential from the fastball.

Anyone have any insight as to who's right? NH clearly thinks the Pirates Prospects Prospect Guide is closer to the target. Who can add to this?