It is a pure scanner\reader but it reads a LOT of data points. It will initiate the ABS purge which you need if you ever change a master cylinder or ABS unit, it will do cylinder contribution tests, injector kill tests, injector return flow set points, read demanded vs actual pressures in the fuel system, trans gov pressure, TTVA positions, etc. Don't think it will set a pinion factor though, that is a write function that a typical scanner does not do. The add on module to do writes and flashes is fairly resonable, a little over $1000 if I remember correctly and that may allow writing a whole lot more things into memory. Have spent hours working with it but we were chasing injector issues so have not had time to dig into every possible function, a lot of things there along with logging.
If you are looking for something to set pinion factor and program things get a Smarty with UDC and the AutoEnginuity for diagnostics\testing. For the about $1100 for both there isn't a better deal out there. With multiple trucks like we have it is well worth the investment, works fine on most things on the 01 also. The Smarty's we are using for the programming which is another long process to figure out the tune unless you buy one.
All the other options are much more expensive. DRBIII tools and bundles are almost $3k anywhere you look and you still need a TechAuthority subscription to get files to flash and they don't allow custom tuning. The StarScan things are a little cheaper on Ebay but still won't allow programming without a subscription.
There is a DRBIII emulator that installs on a laptop that is around $2500 but still need subscription for flash files and no custom programming.
The Smarty UDC adn AutoEnginuity is th ebest deal out there for the biggest bang.