The XBox One's emulation is fantastic in the odd occasion I've used it to play a 360 game - other than the shape of the controller you'd be hard pressed to tell that you're not in fact using an XBox 360.
You can see here[2] some comparisons for Forza Horizon and the difference is quite striking.
[1] https://www.eurogamer.net/articles/digitalfoundry-2016-vs-xb...
[2] https://www.eurogamer.net/articles/digitalfoundry-2018-forza...
I do hope the industry trends towards this.