I run 3 LGs all spring and love all 3 of them. My temps hold great, the humidity holds great. I think it is a matter of getting to know how yours works. I know mine well and know how much to turn the dial to adjust the heat, it is very sensitive. I know that adding more water generally lowers the temp for a little bit. You should use very warm water when adding more. I know how to adjust it when I use it in different seasons, winter and spring are different in temps and humidity. It is extremely sensitive to the air temp and humidity in the room you place it in. Air conditioning is not a good idea. If I read correctly, a blanket was put over the incubator.....the eggs dont get fresh air, they cannot breath, causes poor hatches. Maybe it wasnt so much the incubator as operator error.
Also, it is styrofoam. It needs to be cleaned properly each and every time, no exceptions.
I'm not saying LG has the best design but if you take the time to learn your incubator instead of rushing through things and blaming it first, you will have better success.
*When using an LG, I place on 2x4s the raise it up a little bit. Be careful not to block the air holes on the bottom. Raising it increases air flow into the incubator which helps with hatches. The LG's 'legs' were made too low which does not allow for proper air exchange.
*Always use very warm water when adding water and fill only one reservoir at a time if not sure how much this will increase humidity.
*The temp knob is extremely sensitive, turn a hair at a time and wait, be patient.
*Run this bator for at least 48 hours (at proper temp and humidity) prior to placing eggs in it, using a good thermometer and hygrometer.
*Because it is styrofoam, it is extremely important where is it placed. It should not get any draft at all. You cannot see a draft and sometimes you cannot feel the draft. Before setting up a bator, place a lit candle in the area and check if it flickers at all.
I'm sure there are more tips if I thought a little bit. Bottom line, you need to learn your bator before using it. Some may be designed better, therefore less to learn about it and easier to use. I like my LGs just fine. They work for me, sorry it didnt work for you. I wish you better hatches in the future.