Anivia has better CC and burst, Kennen can be trickier to play but has a better payout in terms of AoE stunning, poking, and mobility.
They both have their ups and downs.
Anivia is generally harder to play, but once you get it down she is easy to master. Kennen is easy to pick up and play, but to truly master him is a lot harder.
I like Anivia a lot. But I haven't tried Kennen. I tend to dislike playing against Kennen as Anivia. Take that for what you will. I vote for Anivia.
I preferred Kennen before his buff, even though the changes were much needed.
Anivia's always a good time.
Kennen. If you have to ask, you're not smart enough to use Annivia.
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