THE NEW REFINE EDGE
This feature isn't necessarily new but you could say it has been overhauled. With the new edge detection feature you can just make a very loose selection and then use this feature to tweak and fine-tune the selection. Then return it as a selection or even a layer mask. Bottom line: This feature takes most of the labor out of creating even the most complex selections.
Great point.
I often use the refine edge as a starting point for my selection. And then I tweak it with mask edge, color range or just good old fashioned brushes.