I use an IPad 2 and a Stratux. Originally I used the Stratux for traffic only and I relied on the internal GPS on my IPad 2 (cellular model with internal GPS), but it would regularly loose GPS signal and my icon in IFly would lock position until GPS connection was reestablished.
About 1 year ago I purchased and added the external GPS for the Stratux and when the IPad is connected through the Stratux WiFi it automatically uses that GPS signal (WAAS) and I have not lost GPS signal since.