Coopers quality has been going down for a couple years. We quit carrying them at my shop last year due to quality control issues, and now if you look they are cheapening the tires... Hopefully the Goodyear acquisition rights the quality once again.
FWIW, Goodyear and Cooper both have factories in China but their production out of China is very limited.. Goodyear has a large market share selling to China, so bringing the Cooper brand to the same market makes sense..
While I have not bought a set of Cooper's in a few years I would not hesitate to run a set of Yokohama tires.
Just cause it is made in another country does not make it inferior. If it is made better then I am going to run the thing. Tires are one of the few items that really can not be brought over and "rebranded" or as American. The amount that is actually "Made in America" may surprise a few people.