^ Truth. it is hard to build a vampire that can do it all. Even though we can build characters that can do more than most, you can't have him take potion and OTS. He can be kitted to be targeted against infantry with bloodshed (in which case take strength in case he gets drawn into combat against high armor models), or kitted against knights/characters (in which case Ogre blade + OTS). Unfortunately, he can't do both characters AND still be a crazy infantry blender.
I would say the build depends on your meta. If you face a lot of daemons, warriors of chaos (ie, armies that usually have troops with decent ward saves) or empire (chaos and empire having good armor), then take Ogre blade or scream blade + OTS. If, however, you face a lot of goblins, elves, skaven, or ogres, then bloodshed + strength would be a viable build, since they tend to have lower armor and more wounds. You could also throw another combat character in the same unit with OTS and keep him next to the ghoul king, so that he removes ward saves for the ghoul king's attacks, or just kit another character for hero-hunting and leave the ghoul king to handle massed troops. Hero vamps can take care of most characters pretty easily with might + OTS and quick blood. He would struggle against chaos lords, ogre tyrants, or high elf princes, but just about any other character he can handle easily enough (and its not like many competitive builds feature a tyrant, HE prince, or chaos lord frequently... most of those armies have a LV 4 as a general which the hero vamp can still smack down). Unkillable dreadlords he also would cause problems with even with OTS, but that is why we have terrorgheists anyway.