We've always advocated diffusors as part of a healthy well-balanced meal... er, acoustic solution. Diffusion can make or break a room. If you only rely on absorption, you can quickly find yourself in a very "dead" space. Diffusion is a way to scatter sound so that you can achieve a pleasant sound without sacrificing that live experience. It;s often the difference between a good sounding room and a great sounding one. The problem has always been that good diffusion is traditionally expensive. Ity has to be since each diffusor is hand-crafted by leprechauns in an isobaric chamber filled with 100% helium. Well, given the prices you'd think that was the case. On the other hand, anybody can throw together some wood pieces and call it diffusion.
Discuss "GIK Acoustics Q7d Diffuser Preview" here. Read the article.