So far this week, I’ve DMed three games of D&D. That’s not normal, I’ve been on leave. So what? Well, on Monday I ran a Pathfinder adventure using OS rules. On Thursday I ran a converted Pathfinder module, reset in Eberron, using 4e rules. Tonight I ran a 2e Undermountain session, updated to 4e, and using OS rules over Google+.
They were all enjoyable, and they all felt like D&D.
Lessons learned? System matters, but not as much as you might think.