A good brush is an essential tool to have. It not only applies clay but can also shape the clay. Sable brushes are great, but not for metal clay. The best brush for metal clay is taklon. The springy quality gives you long-life, stiffness and ease of release of product. Natural hair brushes load too much product up in the bristles. They alsoare not stiff enough to work well as a sculpting tool. My students love the TL078 for using to sculpt the syringe. It also gets paste just where you want it as well.
The Soft Touch Brushes are taklon/synthetic bristles. They will have a long life. The Soft Touch #3 round seems to be bigger/fuller than the Economy #3 even though they are made by the same manufacturer. The #3 Soft Touch is great for applying paste to items. The #2 Soft Touch is a medium size brush for working on smaller items. The #0 is a detail brush and my personal favorite tool.
Don't forget...use dedicated brushes for glazing so that you do not contaminate the colors with PMC particles. We do have great Sable brushes for granulation and also Camel hair brushes for soldering and patina applications.