We installed this plugin due to the all-in-one functionality found in the plugin that we need. Unfortunately it has come to our attention that when visitors are replying to comments via Facebook or Twitter, WordPress is creating user accounts for them. We do not allow anyone to have user accounts on our websites and when the accounts are deleted, it deletes the comments connected to the account. This is a serious flaw in the plugin that we would like to see remedied so we may continue to use the plugin.
Other then this, the plugin performs wonderfully and we're very happy with it.