Hate them, they're awful. All the retail machines my store bought back in 2000~ or so had WD in them. Every one of them has blown it since them, that's like 5 harddrives. Just badly made garbage.
We got a new retail system comprised of new Dells two years ago, and Dell, being the craptacular company that they are, also use WD drives. So far none of them have failed, but the server is getting mighty pokey...