They are too small and lack insulation. They won't hold temps or humidity well. Unless your house is a perfect constant temp and the room isn't too dry you won't get a good hatch rate. You probably won't hatch anything. Some people stick them in styrofoam containers to try to help hold in the heat. You might as well spend your money on a small styorfoam incubator. You can get a basic hovabator for a little over $40 and it will work 10 times better and hold up to 42? standard eggs. Somewhere around there. A hovabator is what I went with. Other people can comment on some of the other small incubators.
I use the LG 9200, it works pretty good, but I have some trouble getting the humidity to go up real high. Other than that, it does pretty good. Humidity stays around 45%, and the temp fluctuates some, between 98-102, but it stays pretty constant. I got mine at my local feed store for about $50, with turner was about $95