Q: Direct3D is good, or OpenGL is good?
A: When you ask when you go to the OpenGL website, you must say that OpenGL is good. If you go to the D3D website, you must say D3D. In fact, these two APIs are doing the same thing, all based on the same hardware as possible, no one is good, as long as you choose a good API, just fine. Each API can make the same horizontal game as long as you play a pole.