I use AccountEdge for three small business. I have been using the software since 1996 when it was marketed as MYOB and was the only professional bookkeeping software available for Apple computers. Since then, I have remained faithful through re-writes and acquisitions. Overall, I really like the software and have found it to be very adaptable to my needs in the different companies (more on that later). I have a small amount of experience with Quickbooks for Mac, so I can offer some generalized comparisons.
I use AccountEdge mostly for ledger entry of transactions, client/contractor/employee information, and to run reports for tax and accounting purposes. I do not use it for its (formidable) inventory, billing, merchant services and invoicing capabilities.