we all know how these things end up, but from another interesting point of view we can prove that opengl is superior to dx:

go to google.com > images
search for directx and then again for opengl

what are results?

opengl:
1 opengl logo, 1 graph flow and the rest (17) are cool screenshoots of stuff made with opengl.

directx:
6 different directx logos, 4 windows dialog boxes (2 are from directx install programs), 1 comparision screenshoot of valve source engine under directx 7, 8 and 9, one image of a woman face that has nothing to do with directx and one wierd nVidia Vs ATI image thing, 1 picture of landscape and 6 screenshoots of stuff made with directx.

it is similar with web results:

directx: first 6 results point to microsoft, its developer center and directx downloads, absolutely no useful info about directx and no tutorials.

opengl:
the cool opengl.org site, opengl specifications, sgi's homepage, some sgi tools and nehe productions (which says "Extensive OpenGL programming tutorials and resources.")

from this i can claim that opengl has much better support and more tutorials & resources than directx.

this is a view onto the situation from another point of view, which may be interesting for everyone.