>> The main reason for choosing DBF over SQL there really is the easy of install as opposed to the headaches that come with installing SQL Express. These apps typically run on thousands of workstations on 5 continents.

An excellent example of practical, clear-eyed thinking.
As much I love the SQL-Server backend. the DBF is the clear choice in this case, at least until something comes along from MS for SQL Server that would work in this case, as I hope it will.