This should be higher up in the comments. DNS is a seldom thought of security / point of failure. Dyn's whole business model is basically: we won't turn you off until we talk to you.
Except Oracle recently purchased DYN. It will be interesting to see if they maintain their previously good reputation.
Recently attended a meeting led by a DYN executive, he seemed very passionate about what they do.
Mirai was an extremely rare event. I understand businesses were impacted, but it's unfair to hold a three-year grudge against any Mirai victims who are otherwise responsible infrastructure operators.