In our group, there are 5 people. 2 of us GM frequently (including me); and 1 has GMed in the past. The other 2 are players only. We have had plenty of d20 games, including D&D & derivatives; but I still say it is hard to find a d20 GM. More precisely, it is hard to find a d20 D&D DM. 3.0 is the best edition in my opinion, but the shine is off the penny for me. I was the biggest proponent of d20 in our group (or groups--past & present). I would still run some d20 games, but D&D is just too hard. And I ran a core game for the most part. Most d20 OGL games approach D&D levels of difficulty, but none really equal or exceed it; and they all just confuse the game. It's just not worth it. It's too much work for not enough play, even with pre-printed adventures. Maybe a succession of low-level games or heavy modification of the rules would work, but I haven't hit upon a way to do it yet.