Not really... here is a quick run down of the three most popular brands.

Sculpey III..... It  is soft, easy to work with, and popular for making sculpted jewelry. It moves easily through clay guns and the colors blend easily which, depending on your point of view, can be a drawback or a blessing.

Premo! Sculpey.....It is softer than FIMO, but stiffer than Sculpey. According to the literature, it is non-crumbling and easy to knead, but still excellent for millefiore. It retains flexibility in thin areas, making small details less vulnerable to breakage. In addition, the colors are carefully designed to mix well, and give you the color results you would expect with art-store paints.

FIMO..... It is the stiffest of these polymer clay varieties, which helps it keep the shapes and colors you want, even when manipulated for long periods of time (for example while detailing multi-layered millefiori canes).

The softer polymer clays are good for projects that don't involve extensive manipulations. They start out easy to work with, but if you are making complex canes, your colors and shapes can start to blend together more than you might want.

The stiffer polymer clays may start out crumbly when cold, but they manipulate well in the long run. You can put a few colors in your pocket for a while to warm them before opening the packages. To warm polymer clay in cold weather, you can point a desk lamp at your clay, or place your clay on a heating pad that's set on its lowest setting. No matter what method you use, be careful not to overheat the clay, or it will start to bake.

If you live in a cold climate, you may also want to heat your work surface before you start working.

If you use polymer clays as a hobby, you can use your regular home oven. Toaster ovens are not recommended, because they don't heat as consistently.
Hope this helps! 

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