So your business is at the mercy of someone else. Whom also has information on all your customers.
What are they going to do, copy my exact appearance and van then turn up and do my work?
that is a fantastic idea.
Look at the end of the day, if it works for you its fine its just my opinion.
However coming from an IT sales background, personally to have my business backed up 'on the cloud' with a third party data center managing that data i feel that its riskier. Don't believe the rubbish that your data is 100% secure, trust me it isn't. if the data exists, and the cloud has access, it can be cracked, it can be accessed, and your business is exposed to a degree.
Much better to have a stand alone system, stand alone database, isolated from the internet. That way you are 100% secure from online hacking, cracking, and being a willing 'captive' customer. These companies can do anything with your data, even if it just to squeeze more monthly subscription from you, for upgrading to this or that.