In 2012 a companion and I hiked up the MR. My companion returned via the MR, while I came down via the Main Trail. We both arrived at the parking lot at the same time. Our time down was 5 hours. I did stop to refill water at switch back #22/23 (10 minutes). My companion said he "took his time" and took several pictures while descending.
For me, the MR is not a good choice for the descent. There are many places where you need to take long steps down, and I find that after a while my knees object to this. You may not have this issue.
I have seen indirect references to people losing the trail while descending, so pay close attention to the route while you are going up. Remember to watch for the pine tree when going back down the E ledges.
Enjoy!
