Bracho, hello! The only difference I found was exactly what is stated on the official WDW website:
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Concierge Service:
Some rooms offer concierge service at the Royal Palm Club and Sugar Loaf, which includes personalized front desk and guest services. Make-up mirror, turndown service, and lounge with continental breakfast, midday snacks and afternoon tea are provided by both Concierge levels. Sugar Loaf also provides a Twilight Refresher in the evening. Wine, cordials and dessert are served at the Royal Palm Club only.
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That is, the RPC had wine, cordials, and desserts. Other than that, they were identical (food, etc.).
Are you thinking about one over the other?