I read recently that John Carmack recommends DirectX for the simple fact that Microsoft, for awhile, played catch-up to openGL and by doing so they created a competitive product and pushed the envelope while openGL folks spent time arguing and doing design by committee allowing DirectX to become polished and, I guess, easier to work with but sticking with openGL.
Maybe another option to consider if you like graphics in general and for what it's worith is what's going on in the embedded space.
I work in the embedded space using both Linux and WinCE. I was former Ford SYNC architect (was there for 6 years) and now I work on GM's CUE (GM's answer to Ford SYNC). Ford SYNC doesn't use openGL or DirectX. Ford, instead, opted for Flash & Action script; what Flash does under the hood I'm not sure but it's slow as hell; JD Powers gave it poor rating. GM's CUE is all Linux and openGL ES and although the GM CUE has a newer iMX processor the performance of animations in openGL on Linux are staggering. CUE/openGL is much faster. Again, Ford crippled their system with Adobe Flash.
So, if you're looking to make it in games but are concerned about the competitive nature but still love this type of work, maybe look at options that broaden your resume. It has been my experience that, at least in the embedded world, WinCE doesn't seem to use DirectX all that much. (WinCE has slightly different API than NT might be part of that reason). OpenGL is everywhere in the embedded world and people are doing more things such as tablets, automobile infotainment is hot right now, and of course smart phones...