I fly with S80 in club aircraft and with LX EOS in my ASW27. My
contribution to your questions in that the S80 has too many knobs and
buttons. The EOS has one knob and one button.

Despite flying with the S80 for 2 seasons I still end up hitting the wrong
buttons and twiddling the wrong knob. The LX offerings are much easier to
operate.

Both are very good varios and provide all the data you need (and much
more).