I've used it a few times when you could still subscribe for $1 for a month. Worst part of it for me was getting the xbox app to play nice on my PC. Seems like it has so many dependencies and if something wasn't installed in the correct order certain games would refuse to start.
In the end it felt like had I given in to letting Windows automatically install every free app it wanted to in the MS Store and surrendering every ounce of privacy only then would it run properly.
I hadn't thought of that. I typically uninstall any MS gaming/xbox crap from my PCs.... I may have to re-install to get the freebee to work.