I stayed at the Rufiji River Camp which is one of the smaller camps in Selous. The proximity to the river meant we had the opportunity for a river safari and a walking safari as well as the traditional trips out on a 4x4.
Selous is wonderfully remote and we hardly saw another vehicle which in my opinion is the best way to experience a safari. The guides were good and spotted a lot of wildlife we may well have missed. The number of lakes meant there was always the chance to see wildlife and birdlife around there. We didn't see all the Big 5 but there were no rhino in the area where we stayed.
I loved my short stay in Tanzania and I will be going back.