Top round comes from the hindquarters: the muscles are frequently used and thus need to be cooked slow and low to really shine. But shine they do! The more an animal uses a muscle, the more flavor results, and the longer the cooking time. (It's why beef tenderloin, which is along the spine and is a relatively unused muscle, is both extremely tender and relatively flavorless compared to other cuts.)
This roast is from a mature cow, who had many, many years to concentrate all of the goodness of plants into exceptionally flavorful and nutritious meat. We then dry age the beef for a month to improve tenderness. The result is something like you've never experienced before in terms of flavor and texture. Find out why this beef is being sought-after all over the world!