I have several models of Carvin HB's in several guitars, I like them. Carvin doesn't have the selection and creativity of Duncam & DMz, or even Gibson, which means you can't always get the right PU for a certain guitar, and magnets are glued in, so swapping is pretty much out. But in the right guitar, they can sound pretty good.
You can get used ones for $20 to $30, and they certainly sound better than any Asian PU's I've heard.