I remember watching a PBS science program that featured a professor and his whole class trying the metal rods method of divining. He was trying to prove the whole notion was hogwash and ended up believing there was something to it after all. He figures it has something to do with magnetism or some other energy; at any rate the whole class had consistent results. They had some teaching assistant bury metal at various locations and neither the prof nor the students knew where on campus they were. Then they divvied up the grounds among them and spread out with rods. The results were good enough to get the guy a grant to do further research.
Can't remember if this was Nova or Scientific American; anyway the upshot was, the metal-finding aspect of divining seems to be way more consistent than waterwitching. The water diviners on the program had more mixed results.
My grandfather was a water witch, he used a hazel branch and family rumor mill had it that he was pretty reliable in his day. I've never had a whack at it but would certainly give it a try before dismissing it out of hand.