No, its a programmable thermostat that will keep you temps +- 1 degree. They are not 'cheap' in that regards... I highly recommend them!
http://reptilebasics.com/Thermostats-p-1-c-250.html
The dial thermostats/rheostats like the reptitemp will fluctuate. Those are quite a bit different. I recommend these for in a pinch, when your really strapped for cash, but that really is my own personal opinion. I am sure others agree.
http://www.reptilesupply.com/product.php?products_id=75