What you are missing could very well be a pair of speakers that produce a beautiful, lush midrange when fed by wonderful 300B amplifier.
300B Advice
I have a Sun Audio 300B and I'm super happy with the sound with JJ 300Bs. Am I missing something though? What happens when I move to an EML or KR or a WE Reissue? Are the JJs on a particular side of the audio spectrum, I assume particularly dynamic.... and if I go for something more textured, will I lose that dynamism. Or do the luxury 300Bs give you both?