This is a blatant copy from fragyou (steelseries blog), but the content is so good that i think it's acceptible that i post it like this - unedited. I hope this will shed some light about mice for the et players who believe 4000 dpi is the BEST THING EVAH! The article is mostly about laser mice, but most of the things mentioned apply to optical mice aswell.

P.S Naturally, the article is a little biased towards steelseries since they wrote it, but everything that's written there is true.