I like the whole aspect of it, that you have them all gathered in a database like system, with auto/manual updating of the plugins.
You don't have to upload via FTP or import any scripts, it's a timesaver!
Under Search, type in the name of the WordPress Plugin or descripitve keyword, author, or tag in the search form or click a tag link below the search form.
Find the WordPress Plugin you wish to install.
Click Details for more information about the Plugin and instructions you may wish to print or save to help setup the Plugin.
Click Install Now to install the WordPress Plugin.
A popup window will ask you to confirm your wish to install the Plugin.
If this is the first time you've installed a WordPress Plugin, enter the FTP login credential information. If you've installed a Plugin before, it will still have the login information.
Click Proceed to continue with the installation. The resulting installation screen will list the installation as successful or note any problems during the install.
If successful, click Activate Plugin to activate it, or Return to Plugin Installer for further actions.
My hope is that XenForo will get there at some point. I believe the Resource Manager is awesome! It has a ton of potential and I would love to see it integrated more into the backend of XenForo like you see with wordpress. Being able to search addons from within XenForo and automatically download and install addons from that search.
I feel the ground-work is being laid down properly and it is only a matter of time .