Here is what the project manager wrote to me:
"My experience with autosomal DNA testing has not been very positive so far. The problem is autosomal DNA dilutes quickly over the generations and after five generations, it is very likely you will no longer share any recognizable segment of autosomal DNA with your relatives. Also, when you are predicted to be related to someone, it is very hard to figure out who your common ancestor might be. I have over 300 matches and have not been able to pinpoint one common ancestor with any of them so far, and I can identify every single one of my 32 great great great great grandparents! On the other hand, my known 5th cousin got tested and she does not share any detectable autosomal DNA with me! So I have to say I am not very impressed with autosomal DNA testing so far and would not recommend it to the average amateur genealogist. It is just too hit-and-miss to be very informative, especially considering how expensive it is."
I trust what this person has to say. She is not referring to African markers, but to European testing which I would assume has a greater probability of finding matches.