Baccano is simple, but it's not done too well. Of the three different arcs, one is awful. That's a third of the show that isn't done well and it ruins the mood for the other two arcs just by being next to them. Fortunately, the other two arcs are good.

The first season of Durarara was neither simple nor done well. While Baccano had only three different arcs running at the same time, Durarara tried to follow many different characters at the same time and the chronology was extremely messy. Baccano's arcs ran chronologically, but parallel to each other. Durarara's plotlines go in zig-zags and it's extremely messy.