I also agree that it totally depends on the scheduler for the client. I have shopped lots for STN for different clients. (JASON ROCKS!) Some of my schedulers have been great, others have not. It's unfortunate. But, when I'm scheduling, the scheduler for the client in my neck of the woods can be a deal breaker.
Roque_Poet, as far as their instructions, I agree with you. For shoppers who are looking for defining guidelines, STN comes up short.