They have used cheese as a topping, I have never seen them serve anything with cheese at Yoshinoya, so this must be the first.
However this dish is slightly weird, cheese is usually grilled or put on top of pasta.
I think I find it hard to accept cheese with yoshinoya beef as the beef is already in sauce, so the whole thing is quite moist and wet and the cheese gets a bit soggy.
The rice was served with triple cheese, Parmesan, cheddar and mozzarella, I felt that if it was plain cheddar, it would have tasted nicer. The Parmesan and mozzarella were tasteless and made the texture stringy.
I was expecting lots of cheese as shown on the product picture, in the real case, I think it was only a third.
In general, it tasted ok, but only cheddar would have given it justice.