In the few games that I played that had both, FSR 3 ran much better than XeSS. XeSS was a little better than FSR 2 (granted, not hard because FSR 2 often runs worse than native for me) but FSR 3 typically had 20+ more FPS than XeSS. Maybe they run better on Intel gpus but those are still too experimental and too low performance for me to even consider at this stage.