The ease of sending out emails to customers. I can see who opened my email and when they did it. This helps me send out more targeted emails with better results. It is also very easy to keep track of which emails have been read by the customer or not. Sometimes their spam filter gets in the way but most of the time it works great. I don't dislike anything about this software. I wish it was easier to delete old emails from customers but other than that everything is fine. I highly recommend this product. Email marketing has never been so simple! I am able to quickly find what emails are open and what emails were just sent. I am able to check how many people opened my email and which ones didn't open at all. This helps me target those who haven't opened my email yet.