IJN Yamato:

Super-Dreadnought or Super-Dreadnought fast battleship?

The top speed I think was 27 knots, but it was launched in 1941, so not blazingly fast for it's day.

I often see it compared to the Iowa class, all around, which I recall are "fast battleships". Though I wonder about the legitimacy of the entire "fast battleship" concept- doesn't it just sound like some naval tactician's wet-dream? The combination of cruiser speed with battleship armor and firepower in a "true" battleship chassis?

I would say Super-Dreadnought, solely for the reason that I've never heard of the Yamato class referred to as "fast battleships".