I think it's worth doing at least once, but I'd lean to breakfast if possible. Eating in (what's left of) the grand canyon concourse with monorails flying by still has some magic. It's an iconic way to fill up in the AM before heading over to MK. The characters are still good, although the service level has been impacted by how hectic it is.
Speaking for breakfast only, I actually think the food is good with a wide selection, certainly on the level of many other buffets with some unique standouts like their cheesy potato casserole. I think it gets shade b/c lunch/dinner is inconsistent, it's wildly loud, and become too expensive (especially when your 10-12 year old eats a mickey waffle and half a muffin for 60 bucks). I'm also not crazy about the newer seating under the monorail.
The real shame is how great this was before chef mickeys, when it was the contemporary/character cafe iterations. Prior to the 90s romper room esthetic of today, it was a more relaxing atmosphere in that older southwest-ish setting with light stone accents and plants, etc Tables were more spaced, with booths available, characters were great/wider ranging and food was much better. A standout was the triangle shaped sourdough french toast rolled in cinnamon and sugar - almost like tonga toast without the stuffing.
Of course, there were no reservations available and often a long line - but if you were lucky enough to stay in the main building on that trip, you could send a parent or family member down then walk outside your room and look down to check their progress. No app needed!