As a vim user, I use Spacemacs for Lisp. Otherwise, I don't like mode inconsistencies (e.g. vim keys don't work inside SLIME debugger), the lack of tabs and the startup/running footprint. It doesn't feel right or convenient to have many Emacs instances scattered throughout tmux or terminal windows, created and killed as needed. Now that I'm thinking about it, this and tabs help me map my work space mentally in a way that hidden buffers (or directory trees) don't.
Although there have been several tab addons for emacs for a while emacs now has native tabs that work the same as vim tabs.
You can run emacs --daemon at login and run either emacsclient to start a new window connected to an existing instance. In my measurements starting vim in a new xterm takes about 250 ms. Starting a new gui emacslient requires only 500 ms. Perhaps numerously running a new default emacs instance with emacs -Q is actually faster at 400ms.
