My experience, and from what I've heard from others, the 'off' brands are not up to the quality of clay like Kato, Premo, Cernit, Fimo, Souffle. Sculpey is okay for certain applications, but it tends to be softer and more easily broken once cured than the others. The quality clays, cured correctly, can be made paper thin, cured, and bent and twisted with no ill effects. It's quite amazing! Each clay brand has it's strengths and weaknesses. A bit of research, and you'll quickly get the gist of it.