The fact is that Hiroo is about as downtown Tokyo as you can get. It's between the bright lights of Shibuya and the mad nightlife of Roppongi. It also borders other upscale residential neighborhoods such as Ebisu, Aoyama and Azabu.
(photo: Hiroo is directly behind the Roppongi Hills building)
Hiroo's central location and quiet streets make it a popular residential area. The neighborhood is (particularly) well-liked by foreign residents of Japan.
There are several good schools (e.g. International School of the Sacred Heart) and hospitals (e.g. Hiroo Hospital) in the area. Hiroo is also home to a number of embassies (e.g. Embassy of Czech Republic).
Several trendy restaurants and bars in the area are frequented by local residents.
Arisugawa-no-miya Memorial Park (Arisugawa Miya Kinen Koen) is a large park in Azabu. It's only a 2 minute walk from Hiroo station. Many people think of the park as being in Hiroo. The park features 16 acres of forest.
(The sign says: don't abandon dogs, cats and ducks.)
The park also features a large pond that permits fishing.
Hiroo is ranked #4 of 21 best places to live in Tokyo.