To realize your goal of flying for a major airline you need PIC time. You'll spend a decade at QX in the right seat. You'll need 2000 hours of SIC time at QX to be considered for an interview at Alaska.

So what's you ultimate goal? If its to live in the Pacific Northwest go for QX. Just realize you may get trapped there for your career.

If its to get a major airline job, find a regional where you can upgrade quickly. Get your PIC time and move on.