A-Headsets are one of the best things that happened to bikes. Fit in ten minutes and then forget till the bearings need replacing a few years down the line, another 10 minute job and needing only a single Allen key. No sodding about hammering cups in, fiddly locknuts and spanners the size of a grand piano, no trying to find that razor edge sweet spot loose bearing adjustment needed, and no having to repeat the whole process again six months later because the crown race is pitted.
Quill stems stink