I have an ugly homemade incubator, it's heated with flexwatt heat tape and has a fan with 4 led lights in it. It's a metal cooler not a styro one and this is it's first run.
Like the brower it has trouble if the room temperature swings broadly and this has been a horrible year for temp swings. So when this hatch is finished I'm going to work on more insulation. I can hatch 24 eggs in it comfortably and I am the auto-turner lol. I may fix that last.
This time it has four bourbon red turkey eggs from my own turkeys and a couple of mutt chicken eggs for this first run.
I didn't like the interior height of the commercial foam incubators, I'm a clutz and kept burning my hands on the heating element when hand turning. I didn't like the lid arrangement for them.
I may make a giant foam one like msprissy's eventually. I'm using most of my sales to save up for a dickey. Building my own in the interim helps me learn what works and why. Which I find useful.