I bought a $20 amazon bluetooth scanner and use the free Torque app for Android. Not sure they make one for iOS devices. I run it on a 7" Nexus tablet.
It works great for a $20 gadget. It plugs in to the port, connect via bluetooth, gives me the codes, and resets the light. Some times it decodes the code, sometimes I need to search google to find it.
The real-time gauges are cool, but not really useful unless your dash went dead and you needed a speedo.
I don't use it much other than code reading...works great for that. Sometimes I have to fiddle with getting the bluetooth to connect,but that's rare.