I think those two units are on different levels.
The IQ Pitmaster should be compared to the Nano-Q as the price is similar and have similar features.
If you are looking at the buget minded ATC's, dont overlook the Auber ATC.
I have one and love it. The best part over the other 2 is it has a bright LED display that tells you the exact temp of your pit, the other 2 dont.
And its more tuneable, but mine has worked perfectly right out of the box.
The most important thing with any of the ATC's is you need a pit that is sealed up well enough that you can put out the coals if you close all your dampers.
The other nice thing about the Auber is it uses a standard thermocouple as a temp proble, so you arent married to the propriatary probes that you have to buy for the other units.