"Very easy to fit, clear instructions. Was very surprised to see that the clock and date were already acurately set when I got it out of the box. Also like the summertime auto adjustment (one less clock to worry about). Easy to use and program. As for reliability, it is difficult to tell as I have only had it for a few weeks. I have a Drayton wireless thermostat that has been in use for about 7 years and that has never let me down so I am hoping for the same from this programmer."