For Mac OS X graphic programmers, if you're trying to do a shading programing using GLSL, XCode already come up with a Shader Builder. Its pretty neat and convenient(with few bugs here and there). The GUI is not as neat as XCode but... okay I can life with that.
But the biggest problem I notice until now is the GLSL ported to OS X is currently not supporting array initialization. I don't know why of all bugs they could make, they chose this one. So don't expect to use loops and friends in your shaders.
Overall, nice attempt, especially for a company that try to centralize every hardware-related development in their office. Just make sure don't fail us AGAIN! *cough java cough*