Yuck to track balls. I wanted an ergonomic and light mouse, The Magic mouse is no good for CAD, it's a looker but not comfortable and also heavy, I researched and got a Logitech M500, it's corded so very light, it's quite large so fits the hand really well, it's fully programmable with any shortcut you want, you can use it all day and realise you are holding it- highly recommended and inexpensive.
I've thought a bout a Wacom tablet- not sure, brilliant for graphics apps though I hear.