I was just listening to some old tunes that were produced by The Neptunes (Pharrell Williams and Chad Hugo) and honestly, not only is their style very distinctive, but it has such a smooth melodic tone to it that stands out from other hip-hop tracks. If I had to put it to a vote, I'd say their sound wins as best production, hands down.
From a purely instrumental standpoint, their production is just clean. Most of the work is done by Chad Hugo. Pharrell is more of a beats/percussion, guy. Chad is better with chord progressions and musical phrasing, in my opinion.