Natural mongoose has been a popular choice for artists because of the combination of strength and suppleness. The Princeton has managed to truly capture the qualities of natural mongoose in their new synthetic line. The brush hairs are amazingly soft and firm. The long shape of the flats and filberts make them even more flexible while retaining a strong "snap". This quality provides the artists with very good control of detail and mark-making, but also allows for a smooth application of paint. The brush clean-up is quick and easy for oil or acrylic. The overall quality and characteristics of these brushes make them a perfect choice for any artist. If I could only choose one line of brushes, this would be the one for me.