There is going to be some variation with any cheap thermometer. I have a bunch of accurites and they work great. I've had a couple of those thermometers from reptile basics and they have all died. They were good while they lasted and I would buy more, but not for $9 a piece. I've seen them much cheaper elsewhere.
http://www.amazon.com/s/ref=sr_nr_n_...nid=2941120011
I use my temp gun for the most part and I have a few random thermometers around just to keep an eye on things.