By default it doesn't load your init.vim, but if you change that flag in the config it will behave exactly like your regular neovim install (since that is in fact exactly what it is: a very light canvas renderer wrapped around neovim). I have been using it for a couple of weeks with all of my vim plugins with no issues (ctrl-p, buffer gator, easy motion, etc).

Edit: it's worth pointing out that while the rendering is done with electron/canvas, everything else is delegated to neovim. I haven't noticed any slowdown with 1000+ line files, but if you're talking tens of thousands... maybe.