I think the biggest factor is their diet. The blacktail I hunt eat a lot of conifer foliage (50% of their diet), and the taste definitely appears in the meat. The whitetail I hunt are Palouse deer, and fatten all summer on wheat sprouts and garbanzo beans. I am not sure they would taste too different were they to be given equal diets. But aging the deer and cooking creatively go a long way to making the odds even! And at the end of the day, any venison is a gift.