And why is that?
A. They only fly from MDW, which is a royal pain. (yes I know this doesn't apply to anyone who doesn't travel to Chicago)
B. I don't like the no assigned seats
C. When flying with a companion who doesn't have Precheck, they don't receive Precheck because companion is on a separate reservation.
D. Their baggage and lack of change fee policy doesn't mean much to me.
Overall it's mostly just me, or me and fellow Chicagoans, but that's my reasoning.