I started the loop at the NE corner (AT crossing at Jug End Rd) and went counter-clockwise. The northern road section was pleasant. SST south was mostly well-marked, but had a few easy-to-miss turns. For several miles after Brace it becomes very technical and little used, slow going. On the southern road section, there are parts of Rt 44 that are a little dicey. I advise caution and avoiding high-traffic times. North on the AT has a killer descent down Bear, the beauty of Sages Ravine, great views from the Race cliffs, and a grueling climb up Everett.
I don't really see any advantages to different starting points or choice of direction. My choices were based on preferences: NE corner for less driving time to get there, and CCW so I could finish on trail instead of road, and be on the AT for the last leg, which is easier to follow so my brain could go on autopilot.
The day was not overly hot, but it was very sunny, and all the time on exposed sections became brutal as the day went on. Water sources were plentiful though, and I made lots of water stops to maintain hydration.