I have nistune and it is good stuff. I think people get confused about changing bin files. with Nistune the base program is already set up. you shouldn't have to change anything with nistune. There are many address files out there that make differences in the ecu tuning. this causes problems. I think this is why nistune sets up per Ecu. Nistune is more direct on which files to use. Also he has great support on his stuff.
I am also a Nistune dealer in CT. There forum has great information on dealing with Issues.