In AutoCAD 2008 (works fine in 2009) and Vista, you can not select the number of colors from solid to 2 or 3 gradient. As soon as you move the mouse down, the popdown selection goes away. My work around was to click on the popdown selection and then use the arrow keys to change from Solid Color to 2 or 3 color gradient.
Also, the color swatches seem intutively backwards. I think of it as reading a book, top to bottom is the same as left to right. On the 2 or 3 color, the left color swatch is the bottom color and right is the top. It would be nice to reverse these or provide labels.
Overall I like these new controls and the background bitmap showing up on the selection button is slick. Along with the HDRI.