I bought my S4 about 2 months ago. It is very light and very stiff. This makes it very fast to move - fast notes and fast string crossings are great. It also responds very fast - with a less stiff bow, it takes half a second or so for the bow to flex or relax when changing string pressure, but this bow is instant. The sound is very clear even playing pp and ff is very loud. I have no doubt that this is the best bow available under £1000.