Something tells me I should try Vengeful more often.
Also yeah, Doom Bringer/Lucifer/Satan is pretty sweet.
I started loving him when I played him and the other team had an overfed Riki. The problem was him going invisible whenever we tried to kill him (this was the typical low-skill pub game too, so no one had a gem or dust), so I used my ultimate on him and he couldn't stealth for the whole duration. That was such a saver for our team.
Not to mention that Devour is both great for gold and getting some extra utility, and his Lvl ? Death taking a chunk out of people is really satisfying.