The amount of code necessary to wire up a well-written application into iOS and Android is pretty minor. I'd rather do that where I can't use GLFW (I mean, GLEW does most of the hard work anyway, and that is portable). GLFW epitomizes a good library for this stuff, in that it's minimal and minimizes the amount of stuff you have to wrestle with when writing C++; on the other hand, SDL forces you to come to grips with its weight and its own dubious design decisions (and a lot of plumbing code to make it sane in C++).

When wrapping OpenGL code myself, at least the dubious design decisions are my own and I understand them intuitively.

  #include <GLFW/glfw3.h>

  int main(void)
  {
    GLFWwindow* window;

    if (!glfwInit())
        return -1;

    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window) {
        glfwTerminate();
        return -1;
    }

    glfwMakeContextCurrent(window);

    while (!glfwWindowShouldClose(window)) {
        /* Render here */


        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glfwTerminate();
    return 0;
  }

VS

   #include <GL3/gl3.h>
   #include <SDL.h>

  /* Our program's entry point */
  int main(int argc, char *argv[])
  {
    SDL_Window *mainwindow;
    SDL_GLContext maincontext;
    SDL_Event event;
    int running = 1;

    if (SDL_Init(SDL_INIT_VIDEO) < 0)
        exit(1);

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
 
    mainwindow = SDL_CreateWindow(PROGRAM_NAME, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
        512, 512, SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN);
    if (!mainwindow)
      exit(1);
 
    maincontext = SDL_GL_CreateContext(mainwindow); 
 
    SDL_GL_SetSwapInterval(1);
 
    
    while (running) {
        while (SDL_PollEvent(&event) {
            if ( event == SDL_WINDOWEVENT_CLOSE ) {
                running = 0;
                break;
            }

            /* render */

        }
        SDL_GL_SwapWindow(mainwindow);
    }
  
    SDL_GL_DeleteContext(maincontext);
    SDL_DestroyWindow(mainwindow);
    SDL_Quit();
 
    return 0;
  }

It's got SDL beat a bit in simplicity for OpenGL, sorry dude.