Yep, it's efficient in it's resource gobbling. The quick templates feature is indispensable for anyone who uses a lot of boilerplate replies in their job, like me, for instance. You can send different autoresponses based on email or content. Lots of features

Oh, and if you happen to use Kaspersky it's spam filtering was made to interface with The Bat!. It'll just show up in the plugins list, nothing to do but configure.