I don't think they are redundant at all. If you have the cash, I recommend you to buy Ambre Preciuex. I have a bottle of LDDM, a sample of Precieux, a bottle of Ambre Sultan and pure oil of amber in a large vial.
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P.S. I also recommend you to try The Sultan (Ambre Sultan) before buying the Precieux. These two are more redundant, and you should decide which one you prefer.