I have four Little Giant incubtors with egg turners, one has a fan, one more for hatching and another one to move the chicks to so they can dry before going into the brooder. The most I paid was $40 for the new ones and another $40 for the new turners. I paid less for the used ones (the one with the fan I bought used since the fan kits cost as much as the incubator). Because I originally got them to hatch duck eggs, which need more humidity than chicken eggs, I wanted still air so the eggs did not get too dry from having air blow on them. Now that I am also hatching chicken eggs I want to find a few fan kits to have more capable of forced air incubation. I know there are more expensive incubators but these work so I don't feel I need to spend more money.
I like having separate incubators rather than one large one because then I don't have all my eggs in one incubator and I can more easily adjust the temperature and humidity as needed. I started out with lower hatching temperatures because I did not realize I needed to increase the temperature for still air but now I have the temperatures just right and I am having good hatches. I know there are problems with styrofoam incubators but other incubators seem to have problems too. I started out with Little Giant incubators years ago and I have always been satisfied with the results. As long as the room temperature is not fluctuating dramatically, the incubators perform well. I need my incubators to pay for themselves so for me cheaper is better.