Best 180* Thermostat Brand
In the past, when a thermostat has failed, it has failed in the closed position. Severely startled me the first time it happened. I thought I blown the engine. I've never had one fail "open".
I've always preferred Robert Shaw Thermostats when I could get them. The company also makes HVAC thermostats, too (won't work in this application). I'll take a brass brand X as a second choice.
Sometimes I can't be picky. In this case, I check the thermostat when I change out the coolant.