OS X as a Game Developer's Platform
This Stepwise article describes one developer's use of OpenStep/Cocoa in his Playstation game development:
To many who have had the pleasure of working with it, Cocoa is the greatest thing since sliced bread. It's been variously described as 95% of the utopian programming environment you've always dreamed of, the way application development should be done, and a decade ahead of its time (even today, more than a decade after its birth as NeXTSTEP). Getting to know Cocoa makes developing on any other platform seem unnecessarily painful and cumbersome by comparison.