My experience is that WN is sometimes more expensive, but by no means far more expensive. This weekend, I'm heading to OAK, and a week ago when I booked, WN was about $5 cheaper than QX (of course I went with QX anyway for the EQM). Perhaps it depends on the market, but to the places I tend to fly to (RNO, SMF, OAK), WN and QX prices are curiously well calibrated to each other. Usually to the penny.