We have taken my nephew who is 3 1/2 to California Grill, and he had an absolute blast. Yes, you have to be prepared for what can sometimes turn into a 2+ hour meal, so if you have really antsy kids you'll have to be prepared.
California Grill is definitely one of those "don't miss" places you should try at Disney if you can. Quite a few of my top dining experiences overall have been at the California Grill. The views really cannot be topped anywhere else in Disney, you can see some part of pretty much every park, and of course the Polynesian, Grand Floridian, and the Magic Kingdom! The outdoor walkway is a must visit if you dine there, if you can time it during the fireworks even better! You really get a birds eye view from up there.
What's great is not only is there an absolutely amazing atmosphere (although I do agree, it can get a bit noisy, especially the more centralized tables), not only do a majority of the seats have great views of the kitchen (for those that like to see the food getting prepared), there is also a great variety of food (and a lot of seasonal pairings). From flatbreads to sushi to poultry to steak, there is almost always something for everyone. I have to say it's one of the most amazingly balanced menus I've ever seen anywhere.
I highly recommend the flatbreads and sushi, they have always been out of this world. And if you're wondering about service, the best waiter I have ever had anywhere in any restaurant was at the California Grill. I believe his name was Tom or Mike, one of those, we never once waited on anything, never once felt rushed, and he took the time to answer all our questions. Not many waiters leave a long term impression, but his professionalism and humble manner won us over early on.
Ok, yea, I like California Grill!!!