I've just installed the Chrome beta on my Mac. Looks good overall.
However the first thing I did ('cause its close to what I'm involved in) was try out the Google Earth Plugin.
So perhaps the same constraints holding back the plugin under Safari 4 are holding up it working under Chrome also; perhaps it is the out of process plugin architecture, and/or the new requirement to use Core Animation to render OpenGL...
Actually I've noticed that Chrome doesn't presently support the Core Animation for OpenGL NPAPI plugins (my CA NPAPI plugin isn't able to instantiate - most likely due to the browser stating that CA/Cocoa is unsupported due to the graceful failure).
In searching for some technical insight I noticed that Google provide a great article on the motivation behind Chrome.
First impressions then are that Chrome looks interesting but it isn't quite there for me yet given my specialised NPAPI requirements.