I have Darwi and Ponart clays, I tried the Ponart one which is not very cheap, and not too light/too soft, but still cracks a lot! So, I stopped doing clay works, because rather than working on the figure, I spend lots of time for the cracks or other fixes.
I don't know about different brands of clay, but cracks often occur when the clay dries too fast. If you keep your project in a mostly airtight container (I use an upsidedown bucket) it should dry slow enough to avoid much cracking. Be careful you don't keep it wet too long, because eventually clay grows mold.