Well it's like I said. The guy will be a UFA. So the Jets can't "commit" to anything besides franchising him at this point. Depending on where the cap comes in, franchising him may be tough. As for comparing him to Mayo, I think Harris is a more complete player. Mayo is a tackling machine. One of the reasons he's got so many tackles is because he plays on the same team as Guyton, TBC, Ninkovich, etc.
As for Spikes, I don't have anything against him (besides the blown coverage on the 58 yard pass to Cotchery). I just don't want to count on him as a sure fire starter given that he's a work in progress on the field, and off the field he's exhibited poor judgment on a number of occasions and already has 1 strike against him with the NFL office.