As the IRMN says, there is no option to download and backup data files on your hard disk or own server.  Everything is in the cloud, which gives you the peace of mind that all your data is backed up constantly with multiple redundancy.  The downside is that you have no way of exporting your data for conversion now or in the future, even to Intuit's own tax products as it stands right now.

You should ALWAYS download a PDF of each tax return you complete for safe-keeping so that you have a record of the actual return that was filed.  (1) There is no way to lock a completed return, which means a finished return could inadvertently be changed subsequent to its completion when someone accesses that return.  (2) Since PTO is updated real time with each new release, your existing returns will be updated without you knowing it if a new tax logic is applied.