I had one for my iPod touch and didn't like it. Yeah, it does show dust and the screen cover thing sticks to the screen of the device way too often. I'd steer clear.
Got one yesterday at Wal-Mart yesterday for $24.98. Put it on when I got home --- very easy, I didn't have problems lining the two pieces up at all.
Some sort of air, oil-looking bubble-thing comes up in between the phone face and screen protection occasionally after you wipe the front of the case. You have to take the phone out and put it back in, and it goes away. I don't know how often this is going to happen, but it may be a major issue for me. Also, the opening for the buttons are deeper than I thought they would be.
We'll see how it goes, but the air, oil bubble thing may make this a problem. I thought the Wal-Mart price was pretty good compared to the online pricing I've seen, so I thought I'd give it a shot.