We can definitely recommend Condado Services aka Terry & Jill. We hired bikes out in May, and we certainly got our money's worth! Terry dropped the bikes off at our appartment at 10.30 am and when we asked him when to bring them back he said 12pm the next day! The only thing is that they don't come with helmets or locks, but no-one seems to wear them anyway. I would suggest taking a small padlock with you if they're going to be out of sight for a while. Also, the spanish drivers seem to be much more considerate of cyclists than drivers over here.
Lynn