I use neither of those and host my own services, but I know I'm a control freak on that.

My point is that an object that you don't control can't be trusted for privacy, that's all. Both iphones and stock android phone fits in this category, you don't control any of those.

Edit : If Apple change it's business model and decide to use the data gathered, what do you do? It's exactly the problem of privacy, having control of the data you consider private. Controlling data over time is a really important part.