Yep, I see the rainbows on movement when white is next to a dark colour (ie high contrasting), or when maybe a white subtitle appears on a black background. It's only for a split second, but it's annoying. Interestingly, mine appear to have changed slightly - they started as thin rainbows, then went though being mostly yellow and blue, and now they are multi-coloured again but seem to be a bit wider than before. Perhaps this means the screen phosphor is changing and eventually after a few months use they will settle down.
As for the blurring, plasma does look softer than LCD but it's percieved sharpness - there is no less detail. Plasma has a more natural look, like CRT. However, it's easy to get drawn into the seemingly pin-sharp pics on LCD, especially for games, but LCD tends to show the flaws in low bitrate video much more because of this. I used to have a Sony Bravia 32V2000U which is a great TV but not a patch on the 428XD.
The crawling you are seeing is noise due to the pulse wave modulation used to make the phosphors work. It's the same with all Pioneers and all plasmas - I think Panasonic manages to surpress it mainly until you hit a certain contrast/brightness level. Switching on the 3DNR might lessen the effect but it general it settles down and shouldn't be a problem from a normal viewing distance.
All this is, of course, just my opinion.
