Try Ruby Satin brushes by Silver Brush. This was the brand that Marvin recommended for our workshop. I had always used natural brushes (sable & bristle) and questioned the quality of synthetics since I'd never used them and had been told by my professors that synthetics were inferior. As with several other 'rule of art,' this was quickly thrown out the window. The Ruby Satin holds paint like bristle and the brush strokes are smoother than sable. I had also bought Rathbone brushes (which are very good) for the workshop and I like my Ruby Satin more.