fishless cycles are much more effective for those that dont have much time on their hands like rbishop said. personally, if i were to cycle a brand new tank right now (granted that i did not have any established tanks around) then i would have to do a fishless cycle because there is no way that i have the time to do daily 50% water changes on my tank during the week. plus, im not really fond of the idea of buying a fish to cycle a tank and then returning it because you only got it to cycle your tank.