That may be a typo on the Paramount page, PJ will have to confirm since he has the notes for both amps.
As far as our amps vs. "very expensive 300B amps", one can use a cheap transformer and feedback all over the place to increase the bandwidth, so ymmv.
My recollection is that the Kaiju offers about an extra half octave of bass, both in the actual frequency response, as well as lower THD in that region.