Decent thermostats?

I used to like Robertshaw but I can't figure out where they went.

I replaced the OEM-looking 'stat in my wife's '94 Acclaim with a Stant
last year. The temperature went from rock-steady at all times to very,
very variable, sometimes approaching overheating when I'd idle in a parking
lot after a good drive. Looking at the brand-new Stant in front of me
next to the OEM-looking oldie, it's obvious the flow hole in the Stant
is considerably smaller.

Went to AutoZone and they sell three no-name brands, all of which looked
to me like cheap tin stampings (though they had about the right size of
flow hole) so I took a pass.

The rubber bushings (!) in the OEM-looking 'stat are cracked badly, or
I'd put it back in.

So who (preferably in meatspace) sells decent auto thermostats?

--
One meter, to within 0.0125% accuracy (off by just under .005 inches):
Three feet
Three inches
Three eights of an inch