My 2 cents...
I love utilizing the Middle Route and have recommended/used it a couple a times to get around the permit for in-canyon camping (and easy access to a car camp.) Note -- you are required to get ALL the way up on the true rim to camp this way to be legal. It's also worth noting that I've seen rangers walking up the Buckskin before checking permits, so be legit.
BUT... having said all that, I would not recommend the route to anyone who is not truly advanced at navigation and/or anyone new to slickrock scrambling or afraid of heights. Finding the right spot can be tricky the first time and when the decent is covered in sand, as it is frequently, the route can be downright scary (and dangerous.)
- Jamal