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!
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 .