Green stuff known as Kneadatite or formerly Duro is flexible when it dries in thin sheets. For this reason it is great for creating natural draping fabric. However, it does not sand well and is not very good if you are a carver. The mix ration of Kneadatite resin and hardener is not critical at 50% each. You can mix more resin to hardener to lengthen curing time but it will eventually cure the same as a 50-50 ration.
Kneadatite can also be mixed with the others to create the best of both worlds and a lot of sculptors have been doing this over the last few years as Kneadatite alone does not sand well at all as it dries like vinyl.
AB putty is the hardest of all of the putties and has great strength. The mix ratio is critical to cure properly.
Andrea and Milliput can be brittle when dry in very thin sheets but are excellent for carving and sanding. Magic Sculpt and Apoxie Sculpt are two others and ones that I personally prefer but good things can be made out of any of them. Milliput comes in different grades of fineness whereas the others do not. It is very sticky until it cures which can be minimized with talcum powder while working. Also the mix ratio of these types is important for proper curing.
