whats the point of getting an expensive one when it does nothing more than what a 5$-10$ mouse can do..! I won't pay extra just for looks unless it really provide something worthy.
Still using Logitech that i got with my system.
depends on what you're doing with it.
i'm working a lot with 3D software/Adobe Suite and with a good ergonomic mouse i'm able to be a lot faster and more precise.
plus i don't get cramps or hurting wrists after hours of clicking. (tendinitis is really ugly while working on a project with strict deadline)
sure they are expensive, but a blacksmith also wouldn't buy cheap tools if he has to use them everyday.