I haven't becaus I'm not running a Debian-base distro. But I doubt that I would: 1. Some privacy features are certainly useful, others are questionable. E.g., why is searching in the Omnibox disabled? If I choose another trustworthy search engine like ixquick or duckduckgo I want to be free to use this feature. 2. Privacy protection is good - but what about security? The latest version of ungoogled-chromium is 49.x from April 1st while Chromium is on v. 51 with many security fixes since then. Conclusion: No, I wouldn't use it.
