What’s the difference between the Brinsea Maxi II Eco, Advance and EX incubators?

The Maxi II Eco is the most basic machine, it uses a liquid in glass thermometer for the temperature reading (there is no humidity display) and egg-turning needs to be performed by hand. You need to turn the eggs 3-4 times a day. Whereas the Maxi II Advance and EX versions have a digital display for the temperature and humidity, as well as automatic egg turning.

In addition to the Maxi II Advance features, the Maxi II EX has automatic humidity control which draws water into the incubator automatically as its needed, accurately maintaining the humidity at the desired level.