I know they both put the gems in your app in different locations but it seems as if bundle install --deployment does a more thorough job. Can I just add the vendor/bundle directory it creates to version control and be done?
I use bundle install --path vendor/bundle
in development mode.
bundle install --deployment
will lock yor Gemfile.lock and will not update it when you change your Gemfile, so never use deployment option on development environment.
bundle install --no-deployment
will disable bundle deployment mode.
You can read that post about bundle usage in right way.