I have the Elm also. I really like it. I have saved data for analysis and graphed signals (mainly for fun) But most of all I have 2 DII's so I keep it hooked up all the time and have different profiles in my Android phone.
I am surprised how much information is obtainable form this. And I don't have a cable running to the diag port. Just the charger if needed. I also Like the Android for Navigation much more superior to the apple
I really like the Elm and Torque App