It would depend on what you like, and what is important to you and your kids. Both are good restaurants, but for different reasons.
Whispering Canyon is a lot of fun, with the servers joking and having races and other hokey little things. Great entertainment, but indifferent food. So if the kids need/ want to be entertained and are going to get stuff that requires ketchup anyway, then go with the entertaining meal at WC. The breakfast skillets there are actually pretty good tho.
If your kids can sit still and enjoy a quieter and perhaps fancier restaurant, then Artist Point shuld appeal. The food is just fantastic and it's a very nice atmosphere. For the quality of the food, the prices at AP are really quite reasonable. Not much to keep the kids entertained tho.
Good luck deciding.