Okay, having eaten at both places on our trip this past June, this is my recommendation:
Both places are good, but they're very different. The most important consideration, I think, is how adventurous are your eaters? If you don't have adventurous eaters, then I think you should scrap Boma entirely. I was downright livid on our last trip when NOBODY in my group would try ANY of the African dishes on the buffet. NOT A SINGLE THING! My husband usually likes to try new things, but even he wouldn't give anything a chance. Not a single nibble! They ate the American-style fried chicken, mac and cheese, etc., and refused to touch ABSOLUTELY NONE of the African dishes. I could've stayed back at our resort and eaten at Cape May buffet, saving myself the long trip over to AK! And it's not like I didn't give them a chance to choose something else before we left. I specifically asked them all about Boma and whether they'd like to try the African food, and they were all game until we got there. VERY irritating.
If you have ANY doubts about whether your party would be willing to try something different, then go to Raglan Road instead.