Take a couple of direct coupled solid-state amps and set them up so that the ouput signal is 10 volts peak to peak. With the same input signal, it is pretty hard to tell a couple good units apart. But take a couple of fine tube amps and do the same thing, and you can often tell a difference right away. One will have a little more bass than the other or something.

Notice I specified direct coupling for the solid-state amps and didn't mention amp configuration on the tube amps. That's a big part of this deal. Many solid-state amps are direct coupled. An exception is Class A amps which are most likely RC coupled. You'll notice some difference between an RC coupled Class A solid state amp and a direct coupled complementary-symmetry solid-state amp. I don't think it is as immediately noticeable as some of the differences in tube amps, but you can still tell.

As for tube circuits, a parafeed amp is likely to be more powerful in the bass than a standard transformer coupled amp, at least if they are about the same power, size and weight. But still, these differences in tubes, configuration and output iron make noticeable differences in tube amps, and you won't generally find such differences between modern solid state hi-fi amps.