If free play weekends become a thing on XBL, I am all for that.
They did it with Forza 5 earlier this year, now Sunset Overdrive.
Even if they can only do it with MS titles, still awesome.
Don't know if I'll actually partake though. I have a lot of unfinished games right now and I was planning on getting SO anyways once I'm done with Unity and Shadows of Mordor.