I did CM golds on two characters in early 2013 with a group over the course of about a month, a healer and a melee dps. Four of us stuck with it the whole way, but the fifth spot (a dps spot) kept turning over as a lot of the people we invited just didn't have the patience to learn it. I think we had four different people in that spot before we finished all the Golds. We only ran for about 3 hours a week though, so maybe 10 hours per toon spread out over a month to get both of them done.
I will say that it took me effort to find a group of people with the right temperament, patience, and skill level to do Gold runs with. I had some false starts before we built our good group. A lot of people just aren't adaptable enough with their skills, or quick enough with their keyboards.
I didn't bother doing CMs on all my alts for exactly that reason - I didn't want to have to find all the people and reset endlessly while they went through the learning curve. I suppose if I had *really* liked and wanted any of the other armor sets, I might have considered paying for a set of runs just to get it over with, on all the alts. And since I know CM gold runs inside and out, and I know how to play all my toons well, I would have definitely been an "easy" carry as I would have done my share of dps or whatever, and not made stupid mistakes.