After struggling with a wired MM for about a year I gave up. The side buttons took too much effort to press, the ball was very jumpy and the 'right click' often was a left click instead...
I now have a Kensington Expert trackball at home and a logitech laser mouse for when I am out on the road. The Expert is big, has 4 programmable buttons, a great scroll ring and it is comfortable to use for hours on end. But, it is not at all practicable for the road. Logitech laser mouse is nothing special, but it works how you want it too, which is more than the MM could manage...
I now have a Kensington Expert trackball at home and a logitech laser mouse for when I am out on the road. The Expert is big, has 4 programmable buttons, a great scroll ring and it is comfortable to use for hours on end. But, it is not at all practicable for the road. Logitech laser mouse is nothing special, but it works how you want it too, which is more than the MM could manage...