I would rather use a can of air duster and clean the bottom of an optical mouse maybe once a month, rather than open up a ball mouse and try and peel off the gunk and dust from the rollers any day.
It may be true that it has the same number of moving parts as a ball mouse, but as far as cleaning goes, I’ll take an optical mouse anyday over a ball mouse.
Or…you could use a mousepad…and never clean your optical…shifty eyes
I use an optical and ball mouse… on the same computer.
Well not at the same time. I have a USB wireless microsoft optical explorer that I mainly use (and I use it on a mouse pad because I have a wood desk that has wood grains that tend to make the cursor jumpy), but it uses batteries. The ball mouse is pluged into the standard mouse port incase my batteries die and I cant find any. Luckily I have plenty.
I have an optical mouse. I like it because I can use it anywhere without a mousepad, and because it has two extra programmable buttons (one on each side). Mostly I like it for the second reason, though.
You mean a trackball? 
I use a Tablet with its mouse. I want room on my desk (so only space for one mouse) and with the tablet I can easily just pick up the pen and use that. Another tablet plus: NOTHING to clean!
We need more options in the poll!
MX DUO!!! The Logitech MX700 Mice are to die for. Best mouse ever. Oh yeah, it’s optical, and wireless.
I’ve given up on ball mice, I’m an optical guy. It’s just smoother, and now the refresh rates are so high that you can game well with them.