I'll put it this way, reviews have always said that the breakfast there is their best meal, and I've done the breakfast a couple of times there, and each time it was definitely the worst breakfast and worst buffet of my trip. That being said, it wasn't that bad, since you asked the question in that way, it's just that comparatively speaking, on my trips which are always 10-15 days and comprise 3 meals a day, it has always been the worst, overall, of my trips, however, not bad or inedible or anything like that. More like average or mediocre or uninspiring as well as messy, dirty, obnoxiously loud, haphazard, chaotic, rushed (in term of character interaction) and overall, rather disappointing for what you'd expect.
But in terms of checking off your Disney bucket list, sure go for it. It's a "classic". I wouldn't waste a lunch or dinner on it, because there are so many better dining options for those kind of meals, but if that's the only time that fits your schedule for a character dining like this that features all the Mickey characters, it's understandable you'd wanna go for it. I think 'Ohana and Tusker House and Cape May Cafe have most of the same Mickey characters, for the most part, though, and their food is much better as well.
