I have eaten several mature bulls from Alaska and the meat was delicious.  Smaller bulls and cows were a little less gamey, but there was little difference.  Moose, in my opinion, is the least gamey of all wildlife.  My favorite is a crockpot roast with lots of garlic, salt, and pepper.  Throw in potatoes, carrots, and a brown gravy for everything and you are good to go.  I have never had the pleasure of eating a shiras though.