> We can iron out issues and make changes over the phone. No mare carrying a USB stick or sending files back-and-forth, it's instant.

A comparable alternative for QuickBooks desktop users is a service called QBox. It lets any number of QuickBooks users at different locations keep a local copy of their QuickBooks company file,  synchronized with all of the other users of that same file. 

I've tried it and it works great, and everybody that uses it a lot tells me it's fairly bulletproof--lots of CPAs and accounting firms use it for working with (sharing) their customers' QuickBooks desktop files.

QuickBooks Online is cheaper if you only have a couple users but QuickBooks desktop + QBox can be cheaper that QuickBooks Online if you have several people using the same file.