I would choose Boma hands down out of the two.
WCC is fun, particularly with kids, but the food is fairly ordinary. Good, but ordinary. As noted, it's also not a buffet, it's a family platter or individual entrees.
Boma is in our families opinion, the best buffet on property. It's probably one of the better ones in the Orlando area. African cuisine lends itself to buffet better than most foods.
Of course, if you (or your family) are not adventurous eaters, your mileage may vary.