The fan controller (and fan itself) cannot monitor temperature. Fans have no hardware to measure temperature with. Your CPU, GPU, hard drive, and certain spots on the motherboard have temperature sensors built in. The BIOS (either of the PC or of the graphics card) uses these readings to adjust the built-in fans automatically. However, if the fan controller does not connect to the motherboard (either via USB or another digital connection like serial) then the controller cannot get this temperature data from the PC and instead relies on its own sensors. You may be able to place these sensors on components you want to measure, but it will only be a surface reading (the PC reading is taken inside the chip's silicon, making it much more accurate).
That said, fans do have a third wire, known as the "sensor wire" or "tachometer wire" which is used for measuring the fan's rotation speed (in RPM). It does this simply by counting the number of times the fan spins or timing the duration between rotations to calculate the rotations per minute. This can give a fairly good estimate of airflow. When you set a fan's speed, you are not setting the RPM but rather the voltage to the fan's motor. Sometimes fans do not scale linearly (so a 2000RPM fan may not necessarily run at 1000RPM at 50% power, it is usually much higher until you get to the very low percentages).
Those fan controllers look pretty nice and sort of implement software (RPM counter and temperature sensors) but I did not see one that can be controlled from the PC itself.
It's really up to you, I built my own because I wanted it to be controlled from the PC (I built one for my server, I work on it remotely a lot so controlling it remotely and monitoring RPM remotely is useful). I also built it for color changing LED's. The choice looks to be knobs or touchscreens for those panel mount controllers. I would get one that monitors RPM, this way if a fan gets stuck it will show 0 RPM, unless it is turned off this indicates a failure and you'll know to check on it.
