Having been to both many times, I honestly believe that "better" depends on the rest of your plans for the day. If you can get yourselves to an 8 a.m. ADR at Tusker House on a day when AK does NOT have morning EMH, then this one is the better choice because you can leave the restaurant at or just before 9 and walk right on to the safari ride before the hoards of people descend in the park. The parks are utterly beautiful early in the morning, when they are relatively deserted.
If you are staying at CR, or if you want to have a leisurely start to your day, OR if you want to get a really early seating so you can get right over to MK for the day, then go for Chef Mickeys.
The differences in the meals and characters aren't significant enough that one would be a better choice than another from a kid's perspective, IMHO.