Pros: Easy to use, set it and forget it (thanks for the phrase Ron Popeil)
My landlord finally agreed to replace our 1950's thermostat with a programmable one and the impact was immediate. The temperature is appropriately controlled at all times of the day and I don't even have to think about it. This model comes with pretty accurate defaults set (4 different time periods in the day, basically before work, while you're at work, when you get home from work, and when you go to bed.) I made some very minor changes and haven't worried much about it since.