I love how easy it was to create my own custom application with all its features, like auto invoice generation upon purchase completion, emailing customers about their orders etc.,etc..
It took me less than an hour to set up everything that i needed in order to have this working perfectly! The customer support team could be more responsive at times but overall they are very helpful when you need them most! There's nothing much really bad that i can say about simplifi (other then maybe some lag