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.
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.