I rarely replace thermostats, probably because I replaced so many when I was using aftermarket thermostats. I never found an aftermarket thermostat worth the work of putting it in. I put four in my Volvo before I got one from Volvo, and it worked perfectly. Original equipment thermostats so rarely fail it hasn't come up in more than a decade. I am sure there are OEM units out there but I never go aftermarket on thermostats any more. Ditto radiator caps and gas caps.
EDIT - cheap thermostats are unstable. The temperature gauge will work its way up, then crash to a little below the correct temperature. Stant is terrible for that. BTW, that doesn't show up if there is only a warning light, or on late model Fords that use the gauge as a warning light.
35 years maintaining my own cars