Ease of use! They are very good at explaining everything you need to know about their software in an easy-to understand way with ample demos/trainings available via webinars or phone calls - we have never had any issues figuring out how this works from day 1 until now when it was needed again recently (we still get support!).
Their customer service has always been exceptional as well!! We do not like some aspects such as having our own account manager which could be beneficial but they can definitely help us without asking too many questions since I am sure there's someone else who knows more than them anyway ;) Highly recommended if your looking into getting integrations between tenants' apps together within one system. You will learn all different types off ways these services work by using trial accounts before committing big bucks :).