To the touch screen, the switching of apps, the delay between the touch of the "next song" and actually playing, the map load, zoom in-out, overall a lot more responsive.... like adding more RAM to a PC
my 2015 Sierra DenaliHD has IntelliLink.... and when i got a rental (Suburban 2015) i saw MyLink.... MyLink is a lot more responsive than IntelliLink... I mean A LOT!! i will ask dealer today when i go get my truck if there is an update for the software