I freakin love it when people ask about one of my favourite animes because I get to rub in my opinion.
If you're going to watch it, keep in mind that it was created by Narita. That being said, it starts with lots of mysteries and unanswered question, but the last ~5 episodes reveal pretty much everything.
You'll get a wrong impression of the story in the first few episodes, but if you stick to it until the end I doubt you'll regret it.
Also, downloading Durarara!!x2 Shou. <3
I was being sarcastic.

