I have heard both. I auditioned both the Helicon 400 and the MS4. To be frank, they are very, very similiar. The highs are very much alike. I think at the end of the day, the difference is that the MS4 are just more articulate through the midrange and the bottom end.. Not much better, but better. I ended up choosing the MS4 and loved them. I had to sell them to move to a smaller place, but I miss them daily.
