OpenGL or Direct3D?

I've been thinking of making some sort of 2d game with little 3d maybe, but I'm not sure which is better/easier to learn: OpenGL or Direct3D. Can someone clarify me what are their strong/weak points, or which is generally simpler or easier to learn, cause I'm not going to do anything big.

Guys. DirectX was made by Microsoft. This is not inherently bad, but keep in mind these guys did the Win32 API. This means you want to STAY THE FUCK AWAY FROM IT.

(P.S.: The Win32 API "gives more control" too, by not doing much itself and forcing you to specify ONE HUNDRED MILLION FUCKING PARAMETERS.)