I just got my wifi unit working in infrastructure mode, which means that it is communicating through my existing wifi router. It has more capabilities this way, including internet access to the control unit, and e-mail and text alerts. It's a bit more difficult to get into this mode, but I believe it works a bit better.
AdHoc mode, which is out of the box, works very easily, will work for anybody with a smart device, it just doesn't have quite the range or capability of infrastructure mode.
This unit does seem expensive, but once you've invested in a kk, come on!
The other thing about the fan units, you better have your grill soaked and close to your target temp before plugging the fan in, or you'll have an overshoot on your hands! Set up properly, this unit will take all guesswork out of temp control on a long cooks, leaving more time for just admiring your beautiful kk!