I don't know about the IQ-110 model, but I will vouch for the BBQ Guru models. I have a DigiQ-II and a 10cfm fan on my 18.5"
WSM and love it. Basic working concept is the same for both, you have a computer module that reads the pit temp and then controls the air flow to the charcoal via the fan.
The IQ-110 has a analog turn dial to set the temp, but you can compare settings to known thermometer readings to make sure you are at your target temp (say 225*). The IQ-110 also does not have a second probe to monitor the food temp. If you have a Maverick or other remote read thermometer, just use it to keep track of your food temps.
They Guru's are more money and ultimately both will do the same job of controlling the pit temperature. The difference in mine and the Pitmaster IQ-110 is mine has digital readouts and settings and I have a second probe for food temp and the unit will alarm at preset food done temps and over or under pit temps. But a Guru is about twice the price of the Pitmaster by the time you add the adapter and fan to the package. There are other brands and models out there. Some are even internet capable and will sync to your smart phone, and other models have multiple pit options to keep track of several pits on a big smoke or competition. You could make a "home brew" version with a simple PID controller and a computer fan if you were handy for probably about half the price of the Pitmaster also.
A power draft (which is what these things really are) is a great tool and on a
WSM will make it about as close to set it and forget it as you can. I'm so familiar with how my
WSM works with my Guru on a overnight shoulder smoke, I know within about 20 minutes of when I will need to add fuel to get me down the stretch. Smoking with a power draft is so consistently repeatable and reliable I no longer worry about getting up to check the pit temps on an overnight smoke. If it has fuel, it will stay at 225*. Nothing like getting 8 hours sleep on a 18 to 22 hours smoke is there?
If I read the
Amazon and Pitmaster web page right, it includes everything for that price and looks like a good deal. Especially if you have some other thermometer to keep track of the food temps with (such as a Maverick).