HGST and its cousin HDS don't get nearly the recognition they deserve in the North American Enterprise storage market. Their products have, in my experience, always offered phenomenal value and rock-solid reliability at very reasonable prices. HDS arrays in particular are pretty great at outperforming 'big name' storage vendors at far lower prices.
I think they changed brands too many times to keep their enterprise reputation intact. Few people even remember that HGST used to be Hitachi which used to be IBM.
On the other hand, those who do remember IBM hard drives probably remember them as the Deathstar, so HGST might not want to be associated with their old home so much.