I've never done the whole loop at once, but I did do half of it in a day, going south just east of Garfield, passing by 13 falls on my way back out. After doing the whole Franconia Ridge, plus Garfield, the thought of climbing up the west side of South Twin just didn't hold much appeal to me. I think it's amazing that people here have been able to complete it in under seven hours, but that's a bit more than I'm looking for.
Personally, I find it much easier to descend steep sections and think if I were going to do the whole looop, I'd rather go at it going counterclockwise. If you go clockwise though the last peak is Bondcliff, which is easily one of the best. Not sure what the difference is as far as elevation gain between the two.