The delay is primarily Vista, since there's little in the existing Spybot S&D main program that needs to change for previous versions of Windows, except the known bug with Win 95.
Beyond that would be feature enhancements to any of the components, including those already being tested with TeaTimer and also the known bugs.
Before you start asking me how quickly to expect the new version, don't bother. I have no idea since I have nothing to do with development, I have simply read everything about what's being worked on in the Beta forum and can see that radical changes have to occur with the scanner, updater and tools as well as their supporting files.
To be perfectly clear, you'll see the final version of the upgrade when it's ready to release. This has always been the pattern with Spybot, since it's not driven by any specific schedule that I've ever seen.
Bitman