It works for my family. We eat at the Crystal Palace for dinner on our first MK day, every visit.
The seats are comfy, the AC works, the buffet provides plenty of variety and we've never felt rushed. And both kids loved Pooh as infants. My soon to be 5 year old still sleeps with her ratty, filthy WinPooh stuffie every night.
I usually steer clear of buffets for fear of food poisoning, but Disney seems to know what they're doing. Their buffet food seems to be held at the right temperature and I've never gotten sick. Crystal Palace specifically - nothing about the food really stands out. I seem to recall some sort of carved meat, salads, carbs, vegetables, nice desserts, ice cream, etc.
I figure we'll keep going until the kids revolt and insist on something different. For me, it's a reliable place to meet some beloved characters and recharge before our evening activities.