I actually read all the reviews on Amazon.com for the MX1000 and for the G7 and ended up going with the G7 (it should arrive next Tuesday). You should probably also check out these reviews before you make a decision (also you can save a nice chunk of change buying the mouse off amazon).
MX1000:
http://www.amazon.com/gp/product/B0002UM...pc&v=glance
G7:
http://www.amazon.com/gp/product/B000AY5...cs&v=glance