kubiakInitial impressions, with less than 4 hours of burn-in, compared to the original Monk:
Less sub-bass
Less mid-bass
More forward mids
More treble presence
Flatter presentation overall
Monk: Thicker, lusher sound with a slightly smaller sound stage
Monk +: More neutral, open sound with a larger, more natural sound stage.
This is volume matching by ear which is not very accurate and difficult since the Monk and Monk + have different impedances. I listened by quickly plugging/unplugging from a V-MODA Vamp Verza. Keep in mind, Lee recommends 50 hours of burn-in before coming to conclusions about the sound, but so far it sounds pretty good.