Not everyone's comfortable wiring up their own incubator from scratch. Some people want to just plug it in and have it work.

Personally, I prefer a stack of Hovabators. If something goes wrong with one, I don't lose all of the year's clutches. Something about not putting all of your eggs in one basket.
I've never found home made incubators to be less stressful. The fact that Hovabators don't come with a good proportional thermostat is just that--you add one. If the unit wears out, you can buy a new one, and use the same thermostat with it. The units are cheap.
Not sure why the hate for the Hovabator, lol. The only people who have issues with them are the people who try to use a wafer thermostat to control temps for ball python eggs.

A modified fridge isn't better, there have been a great many threads with people having issues keeping stable temps in home made incubators.
If you go the 'build your own' route, do it a year before you plan to use, and set it up with empty dummy tubs, so you can make sure that it's going to actually work properly for a whole season, before you risk eggs in it.

Just my opinion.