The frequency to SEA is good and the GEG agents will take great care of you. The frustration comes in trying to get home. The SEA agents (especially the QX ones) are not going to go very far out of their way to help and you will get left behind with an empty jump seat at least once a month. Central Load Planning likes to weight things randomly and the gate agents won’t even let you down to the captain to see if you could make it when the final numbers come in.
That route is also a favorite for line checks since it is so short so randomly you’re out of a jumpseat that way too.