I have rented at SEATAC thrice in the past two months. I have not been impressed, but I usually arrive at about 11:30pm. It's mostly filled with HHR's and Impalas, but you can score a nice car once in a while. Last time I got a RAV which is usually on exec aisle but they had on normal isle due to low inventory. My buddies recently scored a G8 and a nice Equinox with Satellite and leather. They seem to tolerate non-execs taking from the exec row.

One complaint I do have is the cleaning. My first rental was an impala and I discovered a complete batch of trash from a fast food binge in the center armrest storage. The week-old ketchup smelled awful. The second rental had a smear on the driver's window that was just annoying. The third rental had an empty water bottle rolling around in the back. a friend's car had evidence of a spilled beverage all over the dash.