> OSS is dead for five years or more.
OSS on Linux may be dead but OSS is still the API on other free unixes like *BSD's and the API has been developed forwards.
> If you have a SDL+ALSA game you will see exactly zero problems and that's what everybody does.
With SDL, you're stuck with the lowest common denominator of all audio API's. I've had more than my share of problems when doing audio with SDL. If you want 3d audio (doppler effects, etc), SDL audio is out of the question.
OpenAL has been pretty popular with games too, but the implementations available are not rock solid.
> OpenGL support is pretty solid too.
OpenGL support is pretty solid given you have a GPU that has sane drivers, which is not always the case. In particular with consumer laptops and integrated graphics on desktops.
But still, OpenGL is in pretty much every way inferior to D3D if portability doesn't count. It's an awful API for the programmer and the implementer and there are plenty of pitfalls that may cause bad performance or corruptions on crappy drivers.
I regret to say this, but Linux is not a very ideal platform to run games. The biggest problem, by far, is the quality of OpenGL API and implementations. Audio is not at all that bad but it's still kinda hairy.