Bought a size 4 for my 3 year old thinking he'd have a little room to grow, it's already boarderline too small. It fits more like a sweater than a coat. It is puffier than a sweater though. Not sure it would totally replace a coat either because it doesnt seem water resistant. It's an attractive piece of clothing and seems sewn well. Functionality could be lacking or at least varies depending on what your needs are.
Pictured laying on top of an oshkosh coat of the exact same size for reference.
Soft sweater fleece outerwear jacket. Full zip closure, attached hood, and hand warmer pockets.