there are good and bad things about it, personally the wires annoy the hell outa me, so, im going wireless. But it may have some negative effects. Some people have said that you lose reaction time in games. and that the battery may die in the middle of something important.
I own a A4Tech Wireless mouse.. A4Tech has the longest battery life.. I Never noticed "lag" to me.. it's the best wireless mouse out there. Uses RF. Not bad. I had it up to 10 feet away.
I was mad at the wires constantly catching my desk.. so i was about to break the dumb dell mouse (did that later).
I Highly recommend A4Tech, They beat every wireless mouse in every test.. And they are very smoooth.. and cheap.. mine was only 20 dollars at a store.