Well, drums have been around for a while and a lot of people use them as direct fire cookers. I've had a PBC for around seven years and have cooked some great food on it.
Last year I bought a Hasty Bake Roughneck and it does basically the same thing except having the side door to add fuel if need be which I have never had to do because it has a huge fire basket. It also has a second level as well as a heat shield if you don't want direct heat. It's been a great smoker so far.