It really does depend on which facial you go for. There are so many different ones. Some cleanse the skin and clean the pores, some are the ones that are 'supposed' to be the equivalent of a face lift and so on..
I got given one for a birthday present. Was a relxing time with a beautiful girl massageing my face, but came out and 20mins later didn't feel any different at all.
Waste of money if it's yours, nice way to waste half and hour if it's not and you can't be bothered to do anything productive.