Not really, speed does matter. There were once I was suppose to copy 4gb of pictures to my client on the spot after I finish shooting cause they are rushing to somewhere else and they need to take the copy back to their HQ, thank god my 8Gb is 266x, else I would have got screwed by them kaw kaw. Basically it depends on you, if you don't mind waiting for ages for it to copy, you may go ahead on those slow ones.