I do use commercial clays but only now for small objects. I find that commercial bodies are formulated for plasticity and they have more feldspar in them and that`s ok, I think there`s a point at which that`s useful, but I really like working with material in its rawest state.
Typically, I think you can find good clays that have plasticity, yet if you are using clays in their raw states, you may be faced with making compromises; maybe that plastic clay provides really great workability, but it might be a lousy colour, and you have to work with that, and I think thats a good thing. You let the material be what it is; if you are working with a clay that has character and you want to bring that character out all the way through, you`re going to be taking the back seat. I listen to the material, what will it do, what will it not do and it tells me straight away, and that to me is another level of engagement.
I want to use a material that wont do everything I ask it to; I want a material that has something to say on its own and I work with it to bring it through. I think of it as a duet, or a dance.