I have been using Microsoft List Builder previously. You product is excellent. I will be cancelling my List Builder at the end of this month!
We are very happy with the service. Its really the best value out there right now. Period.
I'm pretty stunned at how well your service works -- it's easily one of the most intuitive applications I've ever used. Most important, it seems to work! It took me only about an hour to get a newsletter through the test point. My highest compliments.