The G5 is not a very good mouse. It is beaten in several ways by the copperhead, search google. I don't feel like it right now. The MX518 on the other hand is said to be just as good if not better then a diamondback. So if it's a toss up between the MX518 and a diamondback, get an MX518, but between the G5 and the copperhead, I would have to say go with the copperhead.