wel of course it is in performance.
and u cant say that optical mouse is equal to any other optical mouse. as optical mice ranges from 6£ to 35£ , can u say that the lower price will be as equal in performance as the one with 35 price tag.
if i'd find the MX-510 as the best so far, and MX-1000 being at the top in precision and speed, what else could u expect from it?