Ive used to for 2 years and havent lost any eggs. You do have to split up clutches, but I can fit 30 eggs in there so it definitely holds more than 1-2 clutches.
The things to watch out for:
1. It reads the temp as 3-4F higher than it actually is.
2. The fan only comes on when the heat is on so adding another fan keeps you from having a temperature gradient.
Overall I love mine! Especially because it cools as well and it gets really hot here in FL.