Why do turntables sound different?

It's ALL about the VIBRATIONS! Every part of every TT vibrates! Some more or less than others! And the stylus "reads" these along with the vibrations in the LP grooves. So controlling and eliminating the mechanical vibrations from the TT is a major challenge for designers. And of course some TT's do IT better than others! Rekokut vs. Continuum!

Look at Michael Fremer's set-up in that small room with the Continuum TT and big Wilson speakers! I bet he's not too worried about vibrational interference, since the Continuum is a hefty beast indeed!