Mail is based on short stories featuring one recurring caracther trough the series. every chapter is about it's own ghost with it's own past. because of this you never get any real attatchment to the characters, but that's not needed (after all, they are just bait for the ghost :P). the short stories are introduced in a way so that you can easily get into the feal of it and has the engagement to keep you on the edge of your seat for the rest of the chapter.
the art is clean and nothing special, but it's drawn in very good angles so you
allways know what's going on.
as I said there is only one recurring characther (if you don't count a little girl in the third book, but I wont get too much into that), and he's only there to clean up the mess. as the series progresses you get to know a little more of the main characters story wich gives a meaning to the manga by explaining why he does what he does.
This is where Mail succsedes. for fans of horror this is a must read. it's the first horror-manga that prevented me from sleeping and I had the lights on for 2 nights after that :P
Mail gives a really good scare.
a very good short series for horror fans.