New 360 X1X enhanced games today! Crackdown, Fable, Witcher 2, and Forza Horizon. Already tried Crackdown, definitely a noticeable improvement. Much better aliasing and everything runs good so far, I have tried to tax the system with blowing up a lot of stuff at once and haven't seen slowdown in the way I did when playing on the 360. There may still be some there since I couldn't get big chains of explosions going, but blowing up 3 or 4 cars at once was smooth compared to the 360.
Can also enable/disable the enhancements now for any X1X enhanced 360 title by using the start+select dashboard menu from within the 360 game.
EDIT - Crackdown gif that demonstrates change with enhancements