This restaurant is fantastic!
We went to the Zlaty Klas without looking at reviews, absolutely shattered from a relatively late flight into Prague. We turned up at around 9pm and they had a few people there still.
I took this opportunity to sink into some traditional Czech food and have some Czech beer. I had the '3 meat' dish for 199 Kc, and my partner had the Gnocchi for 119 Kc. Both were absolutely fantastic, and I couldn't believe the price. I had a Pilsner Urquell, which was 38 Kc, which tasted great!
We liked the place so much, we came back two more times on our trip to Prague! I had the Gnocchi the next two times, as it was just so good! My partner had the Risotto for just 99 Kc!
On our last visit, I had a few Dark Kozels (an equally fantastic beer), for just 35 Kc. Sank a few, and we decided to have the Apple Strudel, even though we were both stuffed (49 Kc). This was also fantastic.
I couldn't fault the restaurant in the slightest.
One recommendation? If it's absolutely packed (which it more than likely will be, as it's so good), and all of the tables say 'Reserved' on them, ask if they can accommodate you, as they did for us.