There's definitely a bug in the Stroke department! As soon as I check "Scale with object" the stroke width changes from 20px to 0.4px. And if I want to change that width in the Appearance panel manually I can't... it just goes to 0px no matter what value I type in or even if I scroll with the mouse hover or if I pull the scroll trackbar.
If I uncheck "Scale with object", the stroke goes back to the original value (20px) in the Appearance panel.