A member of our club just brewed a session IPA. He split the batch and fermented one with 04 and the other with 05. It's not a stout, but the two beers were distinctly different. The 05 had a harsher bitterness than the 04 and the 05 was also slightly maltier and not as dry as the 04.
We all preferred the 04 over the 05. With a stout though, you might want the harsher bitterness, slightly maltier flavor and not as dry of a finish.