I've been making sushi for decades. (I apprenticed to a Japanese chef.)
I know the su is very important; I have a vinegar mix that I've been tinkering with for years and some amazing mirin. I have heard that the fresher the rice the less pronounced the differences.
For years I used Kokuho Rose, Calrose, & Nashiki. Several years back I found out my favorite sushi bar uses Tamanishiki and I use it now; I love it's depth. I am, however, always on the look out for new brands.
Another good sushi bar uses Furusato, which apparently means "Neighborhood". (My teacher wanted us to learn about food, not non-food vocabulary.) I have also heard of SunRice and Koshihikari.
Anyone here heard of these brands? Others? Comments?