Initial impressions, with less than 4 hours of burn-in, compared to the original Monk:
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...