I would recommend you stick with iODBC, the
ODBC driver manager Apple has shipped as part of
OS X since Jaguar (10.2). The version Apple
bundles into Yosemite (10.10) remains a bit
behind, at 3.52.6, so I would also recommend you
update to 3.52.10.
iODBC and UnixODBC are built to be API
equivalent, so you should just need to ensure that
your drivers and DSNs are properly configured in
the iODBC locations, optimally via
/Applications/iODBC/). System DSNs
are recommended for most purposes.
/Library/ODBC/odbc.ini # System
/Library/ODBC/odbcinst.ini # System drivers
~/Library/ODBC/odbc.ini # User DSNs
~/Library/ODBC/odbcinst.ini # User drivers