28, and I like it, especially with dark mode.
Generally I'm not too fond of the iOS design due to all the white. It seems as though it was made with the white iPhone in mind. Hopefully we'll get a dark mode there aswell.
The design in Yosemite on the other hand has a lot of grey which I like. Then one can make elements in the interface that are either white or darker than the initial grey base of the interface.
Increasing contrast in some parts of the design would not hurt. Like for instance with the inactive tabs in safari which need to be a bit darker.