I don't think being a fan of the iPhone doesn't mean you can't also be a fan of Android; they're not mutually exclusive (I have an Xbox and a Wii).
Well heck, so do I, but I wouldn't call myself a "fan" of either.
Actually I try not to be a "fan" of anything. Describing yourself as a fan of something seems to be a way of making the rather dull act of liking something into part of your identity.