Ask Maj.-Gen. Wayne W. Grigsby Jr., the top U.S. military officer in Africa, how he thinks U.S. and European-backed African troops are faring in their war on Islamist militants in Somalia, and his answer comes back smartly: "Pretty darn good!"

But when "son of Africa" U.S. President Barack Obama hosts 50 African leaders in Washington this week, the admiration may be less than mutual. Many Africans feel America is lagging behind China and others in its engagement with their continent.

The Aug. 4 to 6 U.S.-Africa Leaders Summit, billed by U.S. officials as a first-of-its-kind event, looks like a belated imitation of Africa gatherings hosted in recent years by China, India, Japan and the continent's former colonial master, Europe.