I find the ability to move comments between posts invaluable because on our busy blog people often seem to comment under the wrong post.
Besides allowing comment editing for a configurable length of time, the plugin has the option of allowing scripts to load in the footer -- a valuable feature on a busy blog.
Plugin also included the ability to disable no-follows, thus rewarding good commenters. And it allows moderators to de-link URLs in both comment content and comment author URL for not so desirable commenters.
Altogether an excellent plugin.
(For a while I was not able to save settings in my network, while individual site installs saved settings just fine. This has now been fixed.)