Overall, I thoroughly enjoyed my time riding around on the Dubai Metro. Even in Silver Class, the trains were clean and well maintained. But with ridership increasing, the Silver Class can be extremely crowded, especially during rush hour. Which is why Gold Class is the way to go.
Even though it does cost more, the experience is significantly better. And while Gold Class can also get quite full, the general ambiance of the cabin helps make the crowd more tolerable.
I've been fortunate to have had the opportunity to travel around the world and experience many of the major metro/subway systems in operation today. In my opinion, Gold Class is simply the best experience I've ever had.
It will be interesting to see how the Dubai Metro system will contend with surging ridership and aging rolling stock in the coming years. But for now, at least, it has a product offering as good as, or better, than any system around the world.