It's an emacs configuration meant to be a hybrid of the best in emacs and vim. I'm a vim user of several years, and am just beginning to do some clojure development of my own, so I recently made the switch.
There's definitely a learning curve, but it's much, much less involved then learning either emacs or vim on their own. And you get to keep the vim editing style.
A couple of things to get used to:
- Space for the leader (it's actually great).
- Escape mostly stops things, but not always. Ctrl-g is a safer option.
- q closes many popup windows.
- Using lisp to do everything in the config file (.spacemacs)
The docs are a good place to start. Also C-h will bring up an extensive help menu.
You'll want to add the clojure layer to your .spacemacs, as one of the dotspacemacs-configuration-layers.
That said a friend of mine recommended some promising vi plugins which look quite good.
I'm also more at home in Vi, but I ended up going with Cursive when I began learning Clojure (and I highly recommend it), but I've always been curious about the Emacs option.