Manufacturing
All-Clad cookware is produced domestically in Pennsylvania. Emerilware is made in China.
Emerilware
Emerilware is single-ply stainless steel cookware. In other words, the pan is completely made up of stainless steel with the exception of the bottom the pan where there is a thick disk of aluminum and copper.
All-Clad
All-Clad's Regular cookware line is made up of triple-ply clad materials. There is a layer of aluminum sandwiched in between to layers of stainless steel throughout the entire pan, not just the bottom.
Similarly, All-Clad's Classic cookware line is made up of multi-ply materials. There are five layers of stainless steel, aluminum, copper, aluminum and stainless steel throughout the entire pan.