As far as Vim goes, it is pretty stellar. Pretty much everything I tried is there and works as expected. There are even some Vim plugins that have been recreated for Evil (i.e. surround).
As far as Emacs goes, well, it has less problems than any other Vim emulation mode, but it still does not play well with everything. It is workable though.
I agree EVIL is pretty good, feels much better to me than Viper/Vimpulse. One issue with any Vim emulation in Emacs is the need to create vim-like keybindings for add-ons, like Org-mode. If you don't do this, and if you use many Emacs add-ons, you'll enter Emacs ctrl-key hell despite having decent Vim emulation.
Below is newsgroup thread with basics of adding Vim-style keybindings to Emacs/EVIL for Org-mode. I chose to make these sample bindings same as those I use in analogous functions in VimOrganizer. (I'm the author of VimOrganizer.)
As far as Emacs goes, well, it has less problems than any other Vim emulation mode, but it still does not play well with everything. It is workable though.