That depends on what you are looking for ... as far as characters Chef Mickey's might be better for a boy although Park Fare isn't bad. In the past Chef Mickey has not been our favorite in regards to food but lately I have been seeing some very good reviews.
We prefer Park Fare for the food. The bread pudding and vanilla sauce, for me, is worth the entire trip .... and price ... even if that is all they had. My DH would disagree. But, we really like the food selection. It is noisy and very busy. But, Chef Mickey's is the same way.
Park Fare has Alice in Wonderland, Mad Hatter (he is wonderful), Mary Poppins (usually outside the door to pose for pictures), Pooh, Tiger, and sometimes Piglet. Chef Mickey's has Pluto, Minnie, Mickey and I think sometimes Chip and Dale. If you tell, either, it is a birthday they will make a big deal out of it ... it is lots of fun.
I'm sure you will enjoy either place. But, our favorite is Park Place 1900 ... it is a must for all our trips (for breakfast).