I've had discussions with three different hosting companies and took an Intuit private class on this.  The ProSeries program is stored in the Cloud at the hosting's location.  You CANNOT back up the data because you don't own the data.  This is the main I said no - the client data is not local to your office.  It is held by the hosting company.  Yes, they may have more people and better security than my small office but I really don't want to give up my client files to anyone else and not have my own copy.  Also the price didn't save me any money at all.