I order the Bad Elf before I have hear of the xgps150 . a few day after order I run into a guy at the airport who be use the xgps150 . after chat about it for a few minute , I decide to cancel my Bad Elf order and order the xgps150 instead . Amazon say it be too late to cancel the Bad Elf . I get the xgps150 and use it in the car and airplane and love it . it be external and connect via Bluetooth . today , I decide to try the Bad Elf that have arrive a few day after the xgps150 . First off , it turn off when you close a app that require GPS . then when you reopen the app , the Bad Elf have reacquire the satellite . very annoying . the xgp stay on and connect . switching between app be seamless . the other issue be that the Bad Elf stick out the bottom of the device you connect it to . it be easily knock out and I believe it would be easy to damage you device . in my hour of use it , it get knock out once . at that point , I firmly decide I would return it . I be go to keep be as a backup to the xgps150 . no more . I 'll be order a second xgps150 .