I can't see or control what information gets sent where. I don't know what gets logged and sent to Google. I refrain from using Google credentials on the phone in case that makes it harder for Google to correlate what happens on my phone with my activity on the web in general. I disable the location services in case that makes it more difficult for someone to watch my location and movements. I don't know if it helps because there is no way I know about to find out what is being logged or where it is being sent.
App permissions seem to be completely coarse-grained, and they all seem to need access to potentially huge amounts of personal data. I can't, so far as I know, disable their access to specific bits of data I don't want them to have; nor do I know of any mechanism for blacklisting or whitelisting access to specific internet hosts.
My Moto X decided a while back that it wanted to upgrade itself and started bringing up a nag screen at frequent intervals, interrupting whatever I was doing. There is no way I can discover to turn this off, and there is no way to decline the upgrade. It just kept nagging me, many times a day, for months. I can't disable this behavior; I can only choose between reduced functionality (getting interrupted mid-sentence and having to dismiss a dialog many times a day) or letting this remote server take over and install its software on my hardware.
In the end I feel like this device doesn't actually belong to me at all. It's more like a rental apartment: I can use it, and I can keep my stuff in it if I want to, but ultimately it belongs to the landlord; which in this case is a combination of Google, Motorola, and T-Mobile. The deal seems pretty clear: they get to decide what I am allowed to do with my phone, they get to decide where my information goes and who gets to see it, and I can either accept the deal or not use the phone. For the most part I have chosen the latter.