The sound of the MS400 is marginally better than the MS300, with better bass and a less colored midrange, but the highs are still softer than headphones like the v-moda M80 and Senn Momentum, which are already soft by hi-fi standards. Detail is a problem for the M400 as much as the M300, and at the regular price, is not a good value based on the sound. Portability is good because of the small stiff zippered case and fold-up action, but takes a hit because of the dual-entry cable that tangles easily. The MS400 is possibly the most comfortable circumaural headphone I've worn. Isolation is modest, so may not be good enough for planes or trains etc.