HoC is not even close to Gjallarhorn. Most cluster bombs miss, and each extra round of wolfpack does nearly as much damage as every cluster bomb combined. And Black Hammer and IB are closer than you think. For most bosses, BH gets the edge. More impact, better sights, recoil. This is coming from someone who's praised IB since the first time he sold it. IB is the most useful exotic, hands down.