Every GUI from every operating system have their own similarities:
Windows Phone:
Meego:
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Android:
iOS:
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Blackberry:
Symbian OS:
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They all have similarities, but as long one is better than the other, you'll have what to choose.
Please tell me one thing, if you can do your own GUI for a phone, will it be a new unique one (implying there can really be something unique) or you will take aspects from other GUIs that impressed you and will build a beeter one based on those aspects?
Touchflo
Unity
Unity is obviously more polished but the similarities are noticeable.