The simplicity and the way the app is integrated with Zuora and Stripe. Also we can integrate with other payment gateways like Paypal. Our main focus is to provide a seamless end user experience. The support is also very good. The only thing that I dislike is that I have to create new projects and then have to add the app engine to the new project. However, this is not a big issue. They should have a better documentation for the app engine. Their support is great. We are using this to build apps for our restaurant clients and the ease of use is amazing. The simplicity of using this is amazing. We are using their app engine for generating apps for our restaurant clients. Also we are integrating with Zuora and Stripe to provide seamless end user experience.