@MBlume - first and foremost, the installation process for me for fireplace was fraught with issues. I installed lein.vim, fireplace, and a bunch of other stuff from all the allied projects : as much as I love vim, it was too much overheard for me to just go through all that! Once I did get it working (and after having worked with emacs/swank/lisp before) - it was just very unintuitive to me. It also feels much slower than cider, and doesn't offer things like the inspector for stack traces and things that cider can. Most importantly, I think the inferior mode in emacs is just a pleasure to use in terms of functionality - I've used it with R, lisp, clojure, and ipython. It's a very neat/clean interface.
There's also the fact that all of these modes are a simple M-x-package-install <package-name> away and they just work. It's kind of like choosing OS X for me after using Linux as my main OS for years and years - I didn't have to worry about the wifi card not being detected or my dual screen display needing a lot of kernel modules : things just work :)
