Miller might not be the best fighter out there but with heavy hands and a fun style he could be featured, somewhere down the line, in a televised bout so we'd advise keeping a tab on him for the next 12-24 months allowing him to develop from a crude slugger to a real prospect.
As well as the style Miller is also a confident and fun individual who has the mouth and personality to interest an American audience and has spent time sparring with both of the Klitschko's.
We don't see Harris as having much of a chance but with Harris power an upset cannot be ruled out.