When our G+ gaming group formed, it was started with the intention of playtesting D&D 5e / Next. That part lasted a few months before leading to DM burnout, which was due in part to both the changing nature of the rules (it was a playtest) and the various expectations of the players in the group that was formed. We were Old School, Pathfinder, 3x and 4e all thrown together. Our expectations were as varied as out gaming backgrounds. There were growing pains.
When our DM asked to take a break from behind the screen, we played a session of 3.5. It ended in a TPK and nearly the end of the group, which is when I offered to run ACKS and DM for the first time in 15 years.
The core of that ACKS group moved on to OSRIC / 1E, and some playtesting of Ambition & Avarice, with the creator ( +Greg Christopher ) playing as a player in his own system. Then some DCC RPG and now Swords & Wizardry - but I'm no longer the sole DM. +Keith J Davies ran some one offs earlier and +Joe D runs his houseruled version of LotFP Weird Fantasy and +David Przybyla just finished putting us through a few sessions of S&W to playtest an adventure he has written.
Yep, we've hit critical mass as a gaming group, where no one person keeps it moving forward, but we all do. It truly is a thing of wonder and I'm so glad to be a part of it. The fact that EVERYONE I game with either is an artist or a writer is amazing, as it simply pushes me to be the best DM or player I can be.
I am finding I really do enjoy being a player, almost as much as being a DM - and I get to drink as a player too! No drinking and DMing for me - my players would run circles around me ;)