What are the different theories of human evolution and their weaknesses?

Although it is established fact that humans share a common ancestor with the other Great Apes, and together with them share an ancestor with all the other apes, primates and mammals, and so on, it is also accepted fact that the details of any hypothetical phylogenetic tree will remain fluid as long as new data is being made available.

In other Words, the details of hypotheses over the exact line of our descent, and those of our sibling ape species, will continue to change as we learn more.

It can be taken as a given, however, that among our ancestors were species like - or at least very similar to - Ardipithecus ramidus, Australopithecus afarensis, Homo habilis and Homo erectus.