When comparing Janus vs vim-plug, the Slant community recommends vim-plug for most people. In the question“What are the best plugin managers for vim?” vim-plug is ranked 1st while Janus is ranked 5th.
Ranked in these QuestionsQuestion Ranking
Pro Builds atop Pathogen
Janus actually uses Pathogen to manage its chosen plugins, and lets you add your own, just as you would with Pathogen.
Pro Great set of defaults
Janus is a great place to start with Vim, with much of the functionality that you would expect from a modern editor, without you having to configure it all.
Pro Parallel plugin installation
Vim-plug uses a fast parallel installation/update process and uses on demand loading for faster startup times.
Pro Simple to set up and use
Vim-plug just requires a single file download to start using, and also requires nothing extra be added to your Vimrc outside of the function calls to start/end defining plugins.