Import and Export are truly outstanding, and actions on the existing users and bounce handling are great time-savers. Overall it is a professional application for any business, and the level of integration with Joomla, Social Networking and Ecommerce is worth the price for the Enterprise version.
Do yourself a real favour and see how a component should be written.
However, negatives aside it works very well and looks good. The very best feature (what I was looking for) is the location cache so you are not constantly going out to the weather site to pickup data, a problem as it slows your site down badly.
Fix the little issues and it would definitely be 5+ stars.