Susan:
I've been to both and, although its Buffalo Steak was out-of-this-world, I was disappointed in Artist Point.
It was the loudest Signature Restaurant I've been in with the slowest service and a messy bathroom to boot. Although the lobby of the Wilderness Lodge is amazing--and I think kids of all ages would enjoy it--for the money, I think
California Grill atop the Contemporary Resort is the more memorable of the two--especially with children.
My dish there was not as memorable as Artist Point (and believe me, I'm all about the food at Disney) but the desserts were better and the view spectacular. And it's the view, not the food, that you and the children will have lingering in your mind forever. Best of all, if you're not in the restaurant when they dim the lights and pipe in the music for the fireworks at Magic Kingdom, you can always come back to the restaurant the same day as your dining experience and catch the show from their outside terrace (which, in my opinion, is better than staying inside the restaurant)!
Wishing y'all a magical vacation!
Whitney