Over the holidays I switched from Vundle to vim-plug as my plugin manager for Vim. While I didn’t run in to any noticeable bugs with Vundle I like the on-demand loading that vim-plug has to offer. That means that you can configure your plugins like this in you .vimrc:

Plug 'mbbill/undotree', { 'on': 'UndotreeToggle' }
Plug 'mattn/emmet-vim', { 'for': ['html', 'css'] }

The on loads the plugin when you execute the command for the first time while the for loads it whenever you open a file with the filetype in question.

After switching out a couple of lines in my .vimrc and adding some for’s and on’s Vim’s startup time decreased with about 100-150 milliseconds on my main machine and 250-300 milliseconds on my old netbook¹. That doesn’t sound like a lot but I can definitively feel it, so to speak.