Hey, I'm just helping to spread the word! A sampled a few links and quotes that has already been posted to blogosphere for your pleasure and knowledge. :)
Download it here -> http://www.codeplex.com/aspnet/Release/ProjectReleases.aspx?ReleaseId=16775
We didn’t originally plan to have another preview. However, we implemented a few significant chunks of functionality and were dying to get feedback so that we could incorporate it into the product before Beta. It helps that with five or so of these interim releases, we’ve become pretty efficient producing these releases.
We plan to have our next release be our official Beta, which means we’ll have a lot more test passes to produce and run before we release the next one.
Some preview 5 related blog posts:
Brad Wilson wrote about changes to partial rendering and view engine in preview 5.
Maarten Balliauw wrote about easier form validation with preview 5.
Nick Berardi has a list of news and changes and also a few issues he's found and submitted bug reports for:
Derik Whittaker had a few comments regarding sealed classes in preview 5:
It looks like that they removed the sealed keyword from many of the Attributes such as HandleErrorAttribute, AuthorizeAttribute and various other existing Attributes.
However, looks like many of the other attributes (some new, some not) such as AcceptVerbsAttribute, ModelBinderAttribute and NonActionAttribute are still marked as sealed. Guys, please unseal all your stuff. If you have a very, very, very valid reason then fine seal them. But if not, let developers loose and unseal them.