One of the features I really liked about CS5 was the ability to modify an existing mask with the Mask Palate. Can't seem to find it in CS6, so if it was taken away, please bring it back! It is such a time saver. If it still exists, where is it?
Also, noticed some dysfunction when placing Photoshop CS6 images into Illustrator CS5. Noticed that color overlay effects and vector shapes don't display correctly. Will this be fixed for Illustrator CS6? On another note, in the past I have not experienced compatibility issues between versions of Photoshop, but have with documents created in CS6 then opened in CS5. Could this be due to different coding?
Other than that, seems to be faster than CS5 and I like that you can continue working in the program while it is saving the background (huge benefit for what I do). Just will take a little getting used to without seeing the "save bar" right in front. Keep trying to close a document that is saving since I'm used to seeing this displayed in plain view.
FYI, You may want to check out the new FAQ post on vector (shape) layers here for some new info: