I disagree. I think a well-timed golden age is extremely useful. I like to time one right around education. While the GA is going on, I probably get at least as much extra research as 1 GP would give me, plus it's in a tech I want, rather than just what the GP will give me. By the time it's finished, I've usually built a University in most of my high-commerce cites and my super-science city is well on its way to finishing Oxford University. If I'm near the top of the pile tech-wise, these 8 turns usually put me ahead of everyone else, with a rapidly widening gap. A GA is also great for building/upgrading a huge invasion force if you're a warmonger.