In my opinion they are the front drum of choice since the hub and drum are one piece, the front hub does not typically have the race issues the pressed steel ones have . As long as they are not pitted up and not way oversize they are my number one choice even over the new cast iron for the hub reason. They are out there but hard to find. The fronts are much more plentiful than the rears. In fact plan on probably never finding the rears ... But the fronts are obtainable here and there with a good eye over time.
The next best are the New cast irons from Mel/randy gross/ Snyders/ Brattons, or other cast iron of your choice in my opinion.
Larry Shepard