Most people will tell you that tube watts sound/seem more powerful. Of course they really are the same in terms of measurement and most people will say the apparent difference is due to the different ways that tube and ss output devices clip and their different harmonic structure (odd order vs even order harmonics). I do not have the technical knowledge to verify or refute those explanations but I can tell you that a 300b tube amp putting out 9 wpc "sounds" way more powerful than a ss amp rated at 15 or 20 wpc.
