Which alternate upgrade for Inferno do you like the most?

By the way, regarding the mind immunity of the Succubus, I was mistaken. They are only immune to mind control. So, they are definitely weaker against Necropolis. And the Imps can steal mana even without Pit Lords – it just disappears. So, if it's important to someone (and sometimes it is), their +1 speed bonus, unlike the Demons, means you don't even need to look at the Pit Lord's upgrade level in your army.