I enjoy Mantlo's run.
I prefer it to Nicieza and Lobdell's runs later on.

The problem is that it was jaunting following straight on from Byrne as the characterization/writing was noticeably different.
I think people would slate Mantlo's run less had it been later on in the title's history; there's still a lot of good stuff in there - characters, ideas, development. It just doesn't all mesh.