On the plus side: cheap Chinese cell phone have allowed Africans at the bottom of the pyramid to communicate in unexpectedly large numbers. On the negative side, counterfeit pharmaceuticals -- a regular phenomenon -- can exacerbate illness or fail to prevent death. This creates a climate of fear and distrust affecting all Chinese pharmaceutical exports. None of these products need to be sold by Chinese, of course. As I've noted in this blog, thousands of African traders visit Chinese cities and export directly from China to their home markets.
While some traders believe that their governments are required to accept Chinese immigrants or traders as a quid pro quo for aid, I have never seen any seen any evidence of an agreement to this effect. Some governments do allow Chinese construction companies to import a proportion of Chinese workers for a project. Some works may stay on as traders. Ultimately, decisions about local competition rest with African governments. In Ethiopia, for example, there are no Chinese retailers on the street.