It's an interesting debate - but I'd like to see contemporary proof that OGL is faster and more capable than D3D. I've been following the Dolphin (Gamecube emulator) development since nearly its inception, and that was originally OGL and its devs argued viciously for the open-source API. Then when they recently ported it to DX9, the overall speed and stability improved dramatically. The article argues well that cross-platform development is better to enable games to penetrate the greatest possible marketspace and that the numbers of PC's which still run on DX9 means that all those DX10/11 developers are missing out on a huge chunk of potential sales - but on the other hand legacy driver issues with OGL are horrendous.