The ease of use! It's been amazing for us. We were able to create our own pages to customize the look of our website. I also love how easy it is to add new pets. We have had many problems with other services, but this one has been so simple and user friendly! There was nothing that we didn't like about the service or the product. We wish they could have more support options other than email. We are solving all our issues right now without calling them. They seem very attentive to feedback and suggestions as well.