downsides to optical mice?

So I'm sick of using ball mice, and how easily they gum up even after you clean them.  i've been thinking of getting an optical mouse

do optical mice have any common problems of their own I should know about?

Some mousemats fuck up optical mice. At my mom's place I have to turn the mousemat upside-down before using the mouse otherwise it's really unresponsive. It's got some kind of hologram worked into it so I guess that's what fucking with it.

Otherwise optical mice are superior. And yeah, you don't need some kind of ubermouse for your gaming. It's more important that it has all the buttons you want and that it fits your hand comfortably than that it has thousands of dpi. You won't notice the difference anyway.