I got my MX700 last night and it is simply amazing. It is perfect, it is much more comfortable than I thought it was going to be, and the tracking is smoother than a baby's ass, and it is very fast and accurate. Without any doubt, this is worth the extra $30, also I am assuming that the MX500 is the same just corded, so either one will do. And the batteries have been going non stop for 13 hours now of pretty much continuous use. So it has greatly exceeded my expectations.
