I recommend purchase of both of these sets, because they have a potential dual market among collectors of Belgian Colonies and the Congo.
With about 66 million people, the Democratic Republic of the Congo (formerly Zaire), is endowed with a vast potential wealth of resources, but has been plagued by wars, corruption, mismanagement, and poverty. Annual GDP growth has been between 6% and 7% over the last 3 years, but little of the new wealth has been distributed amongst the majority of the population, which is extremely poor.
I favor both sets based upon the probable growth in demand for stamps of Belgium and Colonies. Given the economic situation in the D.R.C., I do not feel that a significant stamp market will develop there for at least a decade. If and when the situation in that country substantially improves, however, the increases in value for its better stamps could be quite dramatic.