A few quality vintage USA hammers have not been mentioned here and for the sake of conversation I will mention them. Heller, Atha, Maydole, Plomb and Champion all made very high quality ballpeen hammers. None of these companies are in the hammer business today save for Proto which everyone knows was Plomb. Heller, Atha and Champion all made Blacksmiths Hammers too which by nature had to be durable as they were being used daily. Some of these hammers can be found on the Bay for cheap.
I personally have never noted much difference in quality between one brand and another as long as the handle was tight most hammers do what they are intended to do very well but I am only speaking of older hammers now not any of the new ones.