I also noticed that the display is darker when you first turn it on. After a few seconds, it brightens up. Of the three Pocket PCs, the HP has the worst display as far as clarity and brightness. The display is somewhat grainy looking. You can almost see the individual pixels.
Shapes also tend to bleed down the display.
This bleeding is more noticeable when you're looking at a screen that has a lot of squares or lines. So instead of being able to display images using 65,536 colors, the HP 548 can only display 4,096 colors. This mistake was a big whoopsie on HP's part because people found out after they had bought the units that they didn't get what they thought they were getting. Just using the built in apps and most shareware apps you probably won't notice any difference. It personally doesn't bother me all that much.