I have cooked primarily bb and very few spares so I can't really give many pros and cons. The challenge for me, cuz I don't wrap, is being able to have the thicker end done and tender without overcooking and drying out the thinner end. Who knows, I may yet become a rib-wrapper; I'm a recent convert to the faith of Pork Butt Wrap so anything is possible. I can see how the evenness of stl cut would lend to a more even cook.
Now you've got me itching to try some spares!