The southern circuit is a lot quieter than the northern circuit and at many of the lodges you will not see any other guests when out on game drives. This and the more varied landscape gives the south a wilder and more natural feel.
The game concentrations are similar to the north but in the south the game is spread over a larger area. Distances between parks and lodges is greater in the south meaning that flying is often the best option.
Mikumi and Saadani National Parks are both good destinations if you have limited time for safaris, as both are easily accessible from Dar-es-Salaam. Three to four days would be ideal for the Selous Game Reserve and Ruaha National Park if you fly. With a bit longer you could combine the Selous and Ruaha, or – for safari and hiking - Mikumi and Udzungwa Mountains.