I saw a few early examples of how this plugin was being written and it looked like it would be a nice addition to the WordPress community. I just got it installed on my blog and have been playing around with it and I can't believe everything this plugin can do out of the box already. If you're familiar with WordPress, you can start rocking your email marketing efforts immediately. There's no real learning curve. It's awesome.
Can't wait to see what else they start releasing in coming versions and updates. This plugin is going to be THE email solution for WordPress installs.