Foam brushes are well suited to intricate work such as painting molding or window casings. These brushes are normally good only for one use, as they’re hard to clean and easy to tear.
Manmade bristle brushes are used for acrylics and for water-based and latex paints. Before purchasing a manmade bristle brush, make sure it has a thick head of evenly distributed bristles. Cheaper brushes may have gaps in the middle of the head.
Polyester synthetic brushes are available with straight bristles or split-ended bristles. Split ends give good coverage so fewer strokes are needed to paint a surface. These brushes are used with latex paints.
Natural-bristle brushes are made with animal hair and used mainly with oil-based paints. Latex and water-based paints will dry out the bristles.
When used with latex paint, foam rollers give a finish similar to that produced by a paint sprayer. Foam rollers also come in the shape of a wheel, permitting the user to get into corners more easily.
Source: DIY Network