Hopefully the affected odometers have been rectified by now and the factory have sorted out owners problems on this thread. I tested my GDI (a month old) against the GPS today and it was around 3 MPH over up to 40 MPH and beyond that it hovered from 4 MPH over to 7 MPH over at 75 MPH so overall quite acceptable.
One thing that does irritate though is the way the needle flickers leaving it barely possible to know what speed you are doing without referring to the readout.