This seems to get more confusing, the more answers that appear! I started on a soprano and upgraded to a concert for a little more room between frets and concerts have a bit larger body for a louder and fuller sound. I recently got a longneck soprano, merely for the concert size neck and the benefit of a lower price, because all I wanted was a laminate to have lying around on the coffee table or conveniently hanging on the wall, plus it's the shiny one of my collection.
The term was always a bit confusing to me, since I consider the sizes to be about the neck and fret spacing. Seems like it would be clearer (to me at least) if a longneck soprano was called a small body concert! Maybe some people prefer the concert neck and the soprano sound, which would be hard for me to explain, but my style 0 sounds like what I would describe as a bit twangy or plunky (which I love). And my Martin C1K concert has a fuller, richer sound.