See this comment first, not mine but might as well be https://news.ycombinator.com/item?id=24853678
It's all baby steps. I don't expect to be fully anonymous this way, just like I know my current setup does not foil more sophisticated tracking.
Granted, Tor tries to upstream as much as it reasonably can to FF, but there's still large differences in defaults that could give away (some bits of) your identity.