Where is the data stored?
How long is my data stored?
How often do you perform backups of the data?
Does the client owns the data?
What if I decide to move to another system?
Does the solution have Log Management with audit trails showing the activities done by the web user and the data accessed?
Don't you have saturation problems if every user submit they workflows at the same time at the end of the day?
How safe is our data with you?
In the event of a significant issue, what is the Continuity Plan to recover the data?