I would NEVER recommend using a cheap thermostat on any incubator, and the wafer thermostat that comes with it, while reliable, will give you gray hairs trying to keep it adjusted.
Go Herpstat or Helix. You want a top quality proportional thermostat with a reputation for reliability.
That said, the Hovabator holds temperatures fantastically, usually better than the majority of homemade incubators. I use them exclusively. I tried making a whole closet incubator, but stabilizing it was just an incredible pain. The Hovabators have never let me down...plus, with only 5 clutches per unit, I don't have 'all of my eggs in one basket'....if something were to ever go wrong with an incubator or thermostat, I wouldn't lose everything.
That's definitely something to consider when you are thinking about incubators.
A great big one may seem efficient, but several smaller ones is safer.