I had a friend who worked at Hancocks and she said they had many complaints about Coats and Clarks thread after it's place of manufacture was changed (Was it to Mexico? hmm, can't temember). I have never had any problems with it myself.
Contrary to popular belief, it does not hurt your quilt to use cotton wrapped poly thread. Some quilters will tell you that poly cuts your cotton fabric. it does not. The fabric may wear out before the thread is all.