my experience with the coverage maps, especially MTN, is that it is wildly overoptimistic in some areas, if you go down to street level.
big red sea of HSDPA map coverage does not neccesarily mean great signal or speed at that point, or from experience even real 3G/HSDPA coverage at all.
given up on trying to get explanation from MTN's guys, or when actual HSDPA can be expected, several lodged queries to MTN remain unanswered after months., so wait & see, guess we'll get there when we get there.
best to go and check coverage for your self