It's certainly a time consuming task (there's a lot of square feet on them!) to do a halfarsed job. I clip some of my 'pets', and they fight over who gets to be clipped first.. they're a little skittish about the rattling machine at first, but they understand really quickly how good it feels.. I do it primarily for louse control.. when they go rubbing on stuff they'll get the lice off since there's no hair to hold on to anymore.
I clip with a blade that leaves about 3/8" of hair, but when I only had 1 blade it did about 3/16", and they're *really* bald when it's that short.. I go against the lay of the hair. I do it purely as a functional thing, not for show at all.