I'm with Bamboozle on this one. The paintbrush fibers work great, but are very limited in terms of color, whereas the microfibbetts come in most of the colors you could ever ask for. I use both depending on the size of the fly and how picky I am about matching any particular hatch. I do think the bristles work better on large flies (14 and up). The bugs here that size usually have dark tails that are matched just fine with a black bristle. But the small flies aren't so cooperative where color is concerned so I reach for the 'fibbetts.