Am investigating both the GNS 5870 and the Dual XGP150 for the iPhone.
not because i think the accuracy is off (i can live with a 5m radius) but it chews so much battery running the GC app
Both are bluetooth units with advertised 10 and 8 hrs run times respectively.
as they are claiming to be better/ more accurate GPSRs than the iphones, and 'made for apple' i assume (?) that the phone will turn off its internal power hungry component, and the external unit can work with the app.
The Bad Elf, and the Emprum Ultimate are connected to the recharge plug.
the two problems i see with this configuration is:
It uses the phones battery (battery drain is the only reason i am looking at an external unit so something that uses more is not helpful)
It is susceptible to damage as it hangs out the bottom of the phone or worse yet damaging the phones connection port
As i write this (Nov) am leaning towards the Dual even though it has the slightly shorter battery life (reported between 7.5-8.5 hrs)because
it has a strap so i can attach it to a backpack, jacket, or wrist/watch like
AND a switch so i can use it with my laptop or any NON-Apple device if i need to
retailing in Australia for $144, online for about $85
the GNS has aprox $100 ticket
Would love someones field trial experience or ongoing contribution