How many does it feed?? Also, has anyone succeeded with putting filling in it?

Filling it is easy, just tort with a leveler and pipe icing around the edges and fill! my shaped pans usually feed about 20-30 people.

It feeds 12. I have made it 4 times and each time I bake 2 and layer them that way....too afraid of wrecking her if I were to level like normal. by filling (layering) her you double the serving size. So when I do it I should get 24 pieces, however my family are pigs and I only get 15-20. lol

I would say 20 or more. I've always made these for kids parties and I cut the kids cake slices smaller. They usually waste a lot and I'd rather they come back for seconds then wind up throwing cake away.