The app is very user friendly for our team as it's built in such way where we can easily set up new flows without having any technical knowledge about this platform.
It also helps us build custom workflows which are not available out there when compared to other similar products from various companies like Salesforce etc. I would say nothing much because everything seems perfect at first sight but if you want more features then go ahead otherwise stick with what they have provided. For me personally I am using the product mainly for building customized email templates so far no issues faced during my 5 months experience till now.