My most recent set of beta testing is with the Visual Studio Team System Database Edition. They've got a new release coming out to support SQL Server 2008, but it's also changing the mechanisms the tool uses for builds and deployments. CTP 15 hosed the virtual I was running it on, but CTP 16 seems pretty solid. You just have to plan for the fact that from one release to the next, software or code or projects that worked might stop working. It's a pain, but part of the process of taking part in a beta.