We eat at all three last week. Here are our rankings, dd13 and dd10, dh and I....
1900 Park Faire: We will not eat here again. The food was mediocre at best. There were not as many offerings as other places. You really need to head back to your resort and dress for dinner. I did not feel comfortable in jean capris and a t-shirt. My husband was very uncomfortable in khaki shorts and a tee. Character interaction was good, but frankly not good enough to overshadow the food and our uncomfortableness in park attire.
Chef Mickeys: The character interaction was very good. The characters came around in a speedy fashion and the spacing between tables was decent. The food was okay, not fantastic, but okay. We were perfectly comfortable in park attire and service was good. I would say the food is not reason enough to return, but if you wnat to see the characters in a speedy fashion and avoid autograph lines in the parks, it's a great place to do so.
Crystal Palace: Character interaction is great here, but they do tend to come at a much slower pace than at Chef Mickeys. The tables seem to be slightly closer together, but not quite enough to disturb us and I hate being crowded. The food was quite good and there were several offerings. We were most comfortable here in park attire and I would assume this is because the restaurant is in a park.

We all agree the Crystal Palace is a must do for us. We enjoy it very much.
We did all of these in one week, which was a mistake. Three buffets in a week and all of it starts to be unappealing. In the futre we will pick just one and it will definitely be Crystal Palace. I hope this helps. I fyou have any questions, feel free to ask.