I feel your pain. :)

We're in the middle of this right now.  As Miruna said, there is no upgrade.

We're taking the opportunity to talk with all of our departments about their workflows - what is working, what isn't working, and what are the new possibilities with WF9.  7 to 8 (or 9) is a huge jump in functionality, and most appreciate all the new things we can do for them.

In the worst case, I'm finding that because WF7 had a much simpler feature set it is fairly easy to rewrite those workflows in WF9.