What is your favorite ultimate ability for that class?

Generally speaking, if you consider each ultimate ability separately, they are all very good. It would be surprising if the most recent and difficult-to-obtain ability turned out to be weak. But in my opinion, it's most useful to take it for the Dark Elf, because if you look at the skill tree, you don't need to invest in any unnecessary talents; all the necessary ones are already there. But with other races, you often have to invest in less useful skills instead of more beneficial ones, and as a result, it's likely that a hero with a super-mega ability will easily lose to a hero without it, but with a more well-thought-out build.