Durarara is a slow burn, it's true. Baccano is just on All The Time. I... kind of don't like that they're so frequently compared. I mean, I know why they are, but I think it's not fair. They've both got a huge ensemble cast, but they approach it differently. The newer seasons of Durarara also further expand on all the characters (and introduce even more!). It's great. I love it.
ill grant the last arc of Durarara was pretty good but the one before was god awful.