Has anyone successfully used Windows Workflow for a Business Rules/Validation engine?

Question

I was wondering if anyone has successfully used Windows Workflow Foundation for a BusinessRules/Validation engine, or if you know of some sample code or articles about this.

If you have used it before, what do you think of it? How is it compared to other BusinessRule/Validation systems?

I am thinking of rules like

if (A, B, and C) 
    AllowAccess();

Or

if (Value between X and Y)
    return true;