I thought it was excellent. It really knew how to pull off singular episodes, while still at the same time creating an excellent underlying plot, characters that you care about and are interested in, and great character development. Plus the soundtrack is amazing.
The first 6 or so eps revolve most entirely around the delivery of Shigofumi (letters from the afterlife) to patrons. Then, after that it goes more into Fumiko and how she became a Mail Deliverer, her past, relationships, ect.
The first half kind of reminds me of Hell Girl, or what Hell Girl would have been if had not been so repetitive, cliched, and over the top. The second half is just awesome.
FUCKING WATCH IT