Oz, I have both sizes of EcoGlow brooders and I love 'em. The 50 is easier to adjust the height for growing chicks, but the 20s fit better into my Rubbermaid brooder bins. I have two 20s and one 50.
The big issue with 'em is the need to have an ambient temp of around 50 degrees, so they're not so great for cold locations like a coop in the winter
Knowing limitations of the product is important. Some people expect miracles. Thanks for the input