the software/cable from obd-2.com is what i recommend to everyone. I use it all the time. It reads standard obd data, as well as the Enhanced GM data. Basically, there are only 6 data feeds I can read with standard obd-2 protocols, but with the Enhanced part of the program I have over 100 hundred more. anything from fuel rate, to transmission solenoid status. It seems most other scanner software out there cant get the Enhanced stuff, but charge the same for it. Digimoto is a popular one that I know cant read enhanced stuff yet, even in their latest beta.
And yeah, obd-2.com cant do timing sets, control transmission, turn off individual injectors (for testing), lock the torque converter, etc.
Probably the best $122 I have spent on the truck