I think Chef Mickey's is a must-do if you want to do character dining. It's a bucket list sort of thing. I've eaten there a few times, for breakfast because there was a time when I was obsessed with character dining and it seemed compulsory.
However, the more character dining locations you visit, you quickly realize that Chef Mickey's is the "worst" of the lot, if we're being honest. I feel like you sort of let it's deficiencies slide your first visit or 2 because of the excitement you're at Mickey's place and his best friends are there.
My breakfasts were always good quality but still, would rank the food last of all the character meals I have had (which is almost all of the locations). Only ever had breakfast here, though. Here's the thing. The place becomes a crowded madhouse and isn't designed with enough space to walk around and get your food and every time I have gone here, the food stations get uncontrollably messy and food is all over the floor by them too. This bothered me and became a deterrent to my going back, eventually, when I considered there are so many other nicer character buffets that are cleaner, with better environments for crowd control, and also all with better food. And Mickey is at some of them, too.
That being said, never did lunch there or dinner. But generally, I have noticed it essentially gets the worst reviews of all the character buffets for those meals, as well.