I was one of those people who tried order the Salt, and then order the Function as soon as it was available. The Apple 4K remote had a unique, unadvertised feature - at least in our household. Guaranteed that whoever was using it gained 25 additional BP points. So far, that hasn't happened with the Function. But we're still getting used to it.
I will say that thing I don't like about the Function is it's IR. Have to keep the cabinet door open.
FWIW, our Harmony hasn't played well. It did work well with the older Apple TV unit. Simultaneous to the 4K was a switch to YouTube TV, so retired the Tivo. All this plus a sealed-up 6 year old battery meant the Function was something worth trying.