I think the product is a good tool for small businesses and/or organizations running simple campaigns with small - moderate sized subscriber lists. The customer service and technical support is decent about addressing issues, but they are hard to get to when you really need them the first time. Contact information is buried among layers of self-help advice, which is annoying when you already know that you have an issue that is beyond your ability to pinpoint.
The template building drag n' drop interface is easy to use, but has restrictions. I wouldn't recommend it for people who have very specific designs for their email campaigns. Overall, it's a good affordable option for those with flexible designs and a desire for a simple visual editor.