Thanks for your question. After briefly reviewing the HMCWraps plugin and ItemSkins, I notice some similarities with my plugin. However, there are a few differences that I can highlight.
TheItemSkin offers MySQL support and multiple economies, including Vault, PlayerPoints and TokenManager. It also allows you to hide some skins from the GUI. As an active developer, I am always open to receive feedback and suggestions from my customers. If you have any other questions or comments, feel free to let me know.