Yesterday I had the time to have a first try to this new platform, so I started a new testing website at http://wss.valsania.it/. What I have first noticed is the setup process, dramatically simplified to guide the administrator through the creation of the first WSS webfarm, the search server role assignment, and the whole IIS configuration (virtual sites, application pools, etc.). It is now extremely simple to manage that OS components by using the Application Management site, under the redesigned Central Administration website.
From the user perspective, the new look and feel is simply awesome, tanks to the new Recycle Bin feature (great stuff!), the redesigned Quick Launch, the new “Site Hierarchy”, the Breadcrumbs and “Top Link Bar”. All these components greatly improve the user navigation experience, by reducing the time needed to reach the contents you are looking for.
I have not so much time to spend in testing, but I wish to try at less the migration of site contents from my current WSS 2.0 environment. Hoping to have the time to post further comments about that.