Michael Dahlke

You (the project manager or WP admin) are constantly needing to tell your developer that you added/updated/removed a plugin 
on the live site so he can keep his dev environment semi-synced. This eliminates that need, by just shooting them an email 
with the plugin information and what happened.

Plugin Notifier

Automatically alert your developer when you install/update/remove a plugin.

Gary Pendergast

Advanced Automatic Updates adds extra options to WordPress’ built-in Automatic Updates feature. On top of security updates, it also supports installing major releases, plugins, themes, or even regular SVN checkouts!
If you’re working on a WordPress Multisite install, it will properly restrict the options page to your Network Admin.
While this will be useful for the vast majority of sites, please exercise caution, particularly if you have any custom themes or plugins running on your site.

Advanced Automatic Updates

Nice Plugin

Adds extra options to WordPress' built-in Automatic Updates feature.

Plugin Notifier vs Advanced Automatic Updates