Completely agree with leiningen, it's not an opinionated choice, just what I've seen with maven seems a huge hassle.

In terms of editors I've hit this a bit, attempting to follow tutorials or the like is frequently met with 'step n: install the clojure plugin for Emacs', then 'eval with <Emacs keybinding>' forever after. The Om tutorials iirc are written as tutorials through Light Table (which seems like a great editor). Having to separate learning about the language and how the editor does things just increases the barrier to entry.