dnf is way better than either apt or yum. (Somewhere in my HN comment history I've written at some length about this.)

Major points:

  - dnf has a more complete dependency resolver than apt uses by default
  - the notion of vendor change is extremely useful when managing multiple repositories on a system
  - modern subcommand interfaces are great, and dnf's is stable and mature whereas apt's is still experimental
  - dnf handles repo management itself. apt doesn't