Ah, well...again, if you read the novels and want to recreate the specific setting from them, MHI is a great buy even if you already have the Hero System core books (rules, equipment guide, bestiary, etc). I'd say it's over fifty percent setting specific content with all the flavor text and illustrations expanding on the setting of the novels and many characters fully statted out as NPC's, and you can save on the postage cost buying the PDF....
If you're looking for just an Urban Fantasy setting and intend to customize it heavily in any case, you might be better off building your own. That said, I am not aware of any other Urban Fantasy world setting commercially available and already statted out for Hero System.
Also, here's a more generic, free setting provided by a member of this forum that you might be able to use: http://www.killershrike.com/HereThereBeMonsters/HereThereBeMonsters.aspx