The most mature Clojure development environments right now are Spacemacs/Emacs with CIDER (free) and IntelliJ IDEA with the Cursive plugin (commercial, but inexpensive). Both are excellent.

I'd also add that support in Vim and Neovim are also very good.

Cursive is a very mature project nowadays. I'm surprised at how advanced it is considering how dynamic Clojure is.

So far I've used vim, neovim, cursive and spacemacs and all have solid repl integration. I am generally a vim/neovim user and have been using that for years. It's good. Recently, I've been using spacemacs and like it better. Cursive is pretty solid too though if you're an IntelliJ user.

I would also like to plug Vim. I use it for both Clojure and C++ development, and it handles both like a champ.

I use IntelliJ with Cursive, I have had to do zero configuration, it just works with lein projects.

I will eventually switch to Spacemacs and CIDER once I've really honed my Clojure skills, but for starting out Cursive was what allowed me to learn Clojure in the first place.

Try Atom, following this admittedly opinionated guide. I think you might find it more accessible unless you're already familiar with one of the other alternatives.

https://gist.github.com/jasongilman/d1f70507bed021b48625

The only thing I would add is to try out smart mode in the printer package.

Emacs + CIDER. It's extraordinarily fast, if you're willing to get used to Emacs :)