These are actually my two favorite mouthpieces for soprano. The sound I achieve is similar with both, but they respond differently. Neither of them are what I would call 'dark'. The Yani (#7) is quick to respond, easy articulation, rich altissimo. The SS has a bigger sound in the low notes, but thins out in the palm keys, however it is much easier to subtone with and easier to get a broad dynamic range. THe Yani can be pushed to higher volume levels. I mostly play the Yani, except in small acoustic venues. I'm playing a Yani S990.