Depends on where both were located, or more specifically what they were feeding on. Where I hunt mule deer they often eat a lot of sage and so the meat is somewhat gamey. However, whitetail that I have taken from SE Ohio that live on sticks and browse only is much more gamey. So, as in every aspect of life, it all depends. Overall, I would rate mule deer above whitetail for taste, but they are very close.