These are GREAT.  I have had one on each child's bed for months now.  Even though the kids have played on the beds and the covers have come off, these vinyl covers haven't ripped.  Also, they don't make that annoying plasticky sound when you lie on the bed so they would be fine on an adult's bed.  And they do the job - when the kids have wet their beds, this protects the mattress.  Each time this happens I wipe them down and let them air out, and they don't smell.