I am very impressed by the upcoming workflow 4.0. Although it will force us to re-write many of our older 3.5 and 3.0 workflows, it is definitely worth the price of entry! I am currently building an Advanced Windows Workflow 4.0 course and should be releasing it next week! I can already see that I will be doing a new version in a few months to upgrade it to 4.0! I'll post the outline here next week when I submit to Microsoft Learning! Oh, and here isan awesome rundown on WF 4.0:
http://sergeluca.spaces.live.com/blog/cns!E8A06D5F2F585013!3233.entry
Chris