Lots of people like to use the state machine model workflow as this is a very flexible way of working that often fits in with how real work processes work. With WF3 we had a state machine workflow but with WF4 this was not ready in time and as a result we didn’t get to use this model. There where a few whitepapers on how to do a state machine using a flowchart and for simple cases those worked quite well.
Microsoft also released an implementation of the state machine for WF4 on CodePlex and while that worked quite well it was a not supported scenario making people somewhat nervous about using it in real applications. And rightly so as Microsoft was very likely to move this into the .NET framework proper and not provide an automatic migration path from the CodePlex bit to the final bits.
Now I always suspected we would have to wait for the next full version of the .NET framework it turns out we will get the real bits much sooner. The soon to be released Multi-Targeting Pack for Microsoft .NET Framework 4 Platform Update 1, now that is a mouth full, will contain the officially supported version of the state machine. See here for a how to guide on how to use the state machine.
There are a few references in there to KB2495638 and KB2495593 that don’t work quite yet so we can see what other goodies we are going to get yet but I am sure these links will be operational quite quickly.