Functionally, it's a very nice little unit -- easy to communicate with (a simple command structure, and simple data structure), and easy to do hookups. Internally, the relay channels are independent of the sensor channels. So, in your software you can set up linkage in any way you like. The QK145 is constantly pushing data out the serial line. With the QK190, you have to poll the board for temperature data. The board will work with the same DS1820 and DS18S20 sensors that the QK145 uses, but can handle the DS18B20 sensor as well.