I have listened to both of these mics extensively, as have most people, for the record I love MBHO's and have heard consistently great recordings with them, however the MBHO mics lack the refinement and precise sound reproduction that other mics can offer including the Neumann's, in my experience the 140's will be on a different and higher quality level than will be the 603a's, so unless the 140's are vastly more expensive than the 603a's you should go with the 140's