Light, stiff and (most importantly) the right size for me. went from a non wcs 100mm stem to this wcs version in 90mm and it helped with shoulder pains i was getting on rides that lasted longer than 30 miles. also, im a total ritchey fanboy so i love all their stuff.
Not much to say, but I've used Ritchey stems for a decade or more. Always the finest quality, world class compentry. Strong and stiff, and always the lightest of anything I buy (WCS line).