Davis baking powder is a NY Metro area regional favorite. Hearth Club is currently being sold by Dollar Tree Corp both online and in brick-and-mortar Dollar Tree and their Deals stores for $1 for 8.1 ounces. Most of the store brand baking powder around here is also made by Clabber Girl Corp. If someone has access to a food chemistry lab, it should be fairly easy to assay the contents of the various brands. My guess is that they vary the portions of ingredients for each brand. But I have been wrong about these kinds before, i.e., except for Rumford, they could all be the same stuff.