I do see a lot of people being pretty happy with the 8GB configuration. Many tests shown around, usually show the 8GB keeping up well for a number of tasks.
I mainly went with 16GB because of the "room to grow" workhorse stuff. When it comes to music and video, I planned to go further than before, and user created conditions usually means I'll start using up a bigger pool space of ram, while requiring more multiple levels of simultaneous drive reads. Alas, it was really for creative and performance room, made a bit easier given that I'll get paid for that stuff.
The only snag I hit, from the music part is not a new one, and it doesn't stop anything, and it's more of a issue specifically with MainStage itself. There is a particular set of instrumental and environment overlays that still, when first loading the concert, bring up a message that certain patches could cause issues, totally ignoring the amount of extra power the machine has to overcome it. Just means I have to continue to tell it to ignore that whenever I bring up the concert. It played well enough (with the same complaint) on the Intel machines, but seems like I should do a small workaround to remove the warning message, or wait for a MainStage patch.