I started gaming around '79 or '80, with the blue and red D&D books... I don't often GM. The first game I ran was Shadowrun (1st & 2nd ed) -- because there were no open spots in the one active game in the extended gaming group (about 20-30 people). I ran that for a couple of years. I've also run Werewolf, briefly.
I haven't run d20 for a few reasons. The big one is time. Another major issue is that, based on what I've seen, I think the current set of rules encourages rules-lawyering. My god, *I* have done some rules lawyering, something I once swore I'd *never* do in a game. But when one plays with rules lawyers... Another issue is that there are waaay too many fiddly bits in the rules, almost to the point of Fizbin. ("If it's Tuesday, then... but if it's Tuesday and the moon is full but it's raining, then....") But then I see all sorts of things I've seen that look like they're done "right" and I want to use them in a game, and that ain't gonna happen in any of the games I'm in now.... sigh.
I haven't run d20 for a few reasons. The big one is time. Another major issue is that, based on what I've seen, I think the current set of rules encourages rules-lawyering. My god, *I* have done some rules lawyering, something I once swore I'd *never* do in a game. But when one plays with rules lawyers... Another issue is that there are waaay too many fiddly bits in the rules, almost to the point of Fizbin. ("If it's Tuesday, then... but if it's Tuesday and the moon is full but it's raining, then....") But then I see all sorts of things I've seen that look like they're done "right" and I want to use them in a game, and that ain't gonna happen in any of the games I'm in now.... sigh.