Much has been said about this already, but I'm really annoyed how they repeatedly try to twist this into a technical question like:

"This is better for privacy than how it used to be. Here are 20 reasons why, and we have good scientists who say it offers good privacy. Do you have any technical arguments against these privacy claims? We welcome a discussion about possible flaws in the reasoning of the scientists/engineers in terms of assuring privacy."

To me, that is a secondary question. More important:

• Don't introduce tracking features against my will, with only an opt-out (ironically, while explaining in the same post why opt-outs suck)
• Give room to a discussion about tracking-based advertisements, whether we want to have that in the internet (IMHO no) and support it in firefox of all browsers (IMHO no)
• If they go this way, who is supposed to continue using their shit browser after this? The only reason left is that it's "the reliable other/good browser". People who don't care about these questions are using Chrome anyway.

This is such a self-destructive move, it's painful to watch.