I uses also Logitech mouses. After 1 to 1.5 year, I have to ask to Logitech a new mouse because of the main buttons failures (just Rhinoing, never gaming). Then, 1.5 year later, I buy a new mouse. I have already done this procedure twice. It is a bit annoying to have to contact the support but then you have a new mouse and you keep the old one as backup.
I have now a G700. I appreciate it because it is cord / less and I get my main Rhino functions on the mouse buttons (move, align, rotate, rotate3D, symetry, select and hide, project CPlane, tab, escape, delete, shift, ctrl, alt). All these functions are kept in the mouse memory, so I can change computer and keep my buttons features.
http://img16.imageshack.us/img16/5503/logitechg700wirelessgam.jpg