Pixelapse has put together a great blog entry comparing some of the the graphic design elements of Yosemite with those of Mavericks, picking up on some of the subtle touches that many may not yet have noticed – like the translucent notification badges on the dock …
Annotations point out the changes, like the smaller Apple logo in the menu bar and thinner icons.
The author also points to some of the things Apple is still tweaking, like the three different versions of forward/back buttons in use.
The page is well worth a visit if you haven’t yet tried the beta of Yosemite and want to get a sense of the look – and even if you’re testing it at present, you’ll almost certainly see things you hadn’t yet noticed.