We like it, our (expert) clients like it, and it has the "Oh, cool!" factor.
That said, we do walk on tiptoes around the "ban" functions -- twice, new code has conflicted with existing directives to no good end. It's a relatively easy fix, if you have a fairly simple .htaccess file or a copy of your current one. But for now, we're simply copying IP addresses from the plugin's report and pasting them into .htaccess manually. Only this prevents me from giving it five stars.