The higher the fill power, the longer the firmness or fluffiness will last.
Down and feather have the tendency to cave and lose their fluffiness in a much shorter period of time, and wool can flatten out when used often.
Down comforters are known for their fluffiness, softness and plush feel.
Just the same as you would likely consider when shopping for an actual down comforter, it is important to choose an alternative comforter that mimics the warmth and fluffiness of the real thing.
Parents should be careful washing stuffed toys as they tend to lose their shape and fluffiness after repeated washings.