Tough to say. There are only a few long running series that I enjoy reading (such as Hajime no Ippo or Negima), but generally, the stories are strained and too long winded - and of course, possibly cashed-in on.
Short series just seem to get to the point, and give you some sort of finale. The irony is, depending on how well it draws you in, sometimes you wish there would be more.
Preference; short. In and around 14 Volumes of manga should be the longest run for most manga - that way there's a bit of breathing room to draw the story out, but at the same time, just enough leeway to give it a proper conclusion.
__________________
*Click for Youtube*
|