Google does a lot of things but they've never betrayed my trust by installing an extension in conjunction with a third party without telling me.
Google does track a lot of my data but they provide useful services in exchange, and in addition they make it pretty easy to see what data they have on me. Also Google's data is its competitive advantage so our interest in protecting my data from 3rd parties is aligned.
In short, Google tracks me sure, but they're pretty transparent about it. I do think some of the things Google does with Chrome and it's market position is less than stellar so I'm still exploring other options. If you have any suggestions I'd be happy to hear them.