Regarding the posts by a number of people about trackballs, I have had some positive experience with trackballs primarily with one that is no longer made. My problem is that I am left-handed, and it seems like all trackballs are for right-handed people.
I bought the M.O.U.S. 9 from Mad Catz and I have had several issues. Primarily after programming the buttons not funcioning properly.
Personally, the best mouse I've used for my Mac was the Logitech MX REVOLUTION (NOT MX Performance - worthless replacement). The Revolution has been discontinued for close to 3 years now. . . Mine was 6 yo when I finally replaced it for the M.O.U.S 9.
This mouse is a dumbed down version of the Revoultion (which is out-of-production). You should understand that the current Logitech Control Center software driver (ver. 3.9.1) does NOT work at all with Yosemite. Lots of people are reporting this issue on many different sites like this one.
Upgraded to Yosemite. Logitech Performance MX mouse will point, but the buttons on mouse do not work. Tried re-booting, reinstalling the Control Center software driver and changing the USB port the receiver is plugged into. Nothing works. Searched on Logitech.com for new, updated driver -- there isn't one! Called Logitech (646) 454-3200 -- waited 25 mins / was disconnected. Called again; waited 25 mins - finally got some hollow support guy who knew NOTHING, repeat NOTHING, about when or IF there would be a driver update. Even spoke to a supervisor - same.
FIrst, I think this IS a software driver issue. My Kensington mice and trackballs work just fine. Second, Logitech customer support has to be one of the worst I've encountered. Regardless, I suggest that everyone call them and demand a driver update that works with Yosemite!
the Logitech Performance Mouse MX is the best mouse i've ever used. i also use my Wacom Intuos4 tablet pen as a mouse at least 50% of the time. i've never been a fan of any Apple mice...can't stand em'.