My sister and me both bought these back in spring. They are not bad incubators. The only problem I have had is that the temp won't stay consistent especially at hatch but that could also be because I'm inexperienced at incubating.
I haven't had any real problems with mine after 4 hatches. In the middle of summer the temp did climb a little but the sun was shining on it all afternoon and I had nowhere better to put it. I just turned once in the afternoon to vent the heat. If you keep your house around the same temp or have a stable room/closet they work fine. If you let your house go through temperature changes from day to night most of the styrofoam bators won't do well. They just don't hold the heat well enough.