Folder Based settings allow each folder to have it's own zoom, and it's own view type (list view, icon view, compact view). While one global setting means there is only one zoom setting and one view setting and it will be used on all your folders.
At the heart of this, is the question are all folders the same. For me they clearly are not.
Folders that contain photos and videos are different to others as you will prefer to have see them displayed in icon view and with a higher zoom level.
While with a folder consisting of variety of file types I would prefer the list view and normal zoom. For the downloads folder I would prefer to have contents ordered by a descending date. For folders like /usr/bin I would prefer the compact view.
With a folder based settings all those settings mentioned above are remembered when you open that folder in file manager. While with one global setting you have to adjust all those again every time you open the folder.
I was wondering what people prefer.