Yes folks. You should be completely confident in Blizzard. I mean, the night before how many tens of thousands of people from around the world try to order tickets, the authentication servers go down. Many users are experiencing it, however a few are not.
What on Earth could go wrong tomorrow?
Reythur, a Blizzard blue poster, has said that the issue is being investigated. We'll update this post with more information as we get it.
Update #4: Things are working now it appears for all Battle.net accounts and all regular accounts.