I see no reason why it should judder at this speed, I can tell you without question that any decent CNC machine would easily move at this speed and slower without juddering. It wouldn't be much use if it didn't as those vibrations your feeling through your feet would show in the cut quality.

To me I can't see why if it was setup correctly without binding or anything being bent, etc, and securely fastened down why this linear stage should vibrate.