It's my understanding the the GPS that comes with the DJI Naza Lite is the same as the GPS that comes with the DJI Naza V2.
The GPS inside the DJI Naza GPS is a uBLox Neo 6. It only tracks USA GPS satellites, not other country versions of these satellites. Newer (non DJI/Naza) GPS units use more satellites. so the clone GPSs will track more satellites than the authentic ones. I think i've found that newer GPS units have more problems with more/worse sudden "jumps" though.
All the DJI GPSs have mags and only need one port, that is why they are desirable.