I go to this QFC regularly as someone who does shopping for a local theater during productions. As others have mentioned, the parking lot is exceptionally small and hard to navigate, but that can be traced back to when it was built and the insane population growth that has happened since - not much to be done about that.
The service has always been good - never had a bad experience there (knock on wood). But last weekend (Sunday the 16th at around 12:30 pm) we had a tremendous customer service encounter with the person working the self-checkout. We run a non-profit, so it's important that we spend as little money as possible on our concessions and stuff - so we picked up a case of bottled water for what we thought was a great deal. But when we rung it up, it didn't go through as on sale. We didn't notice until we'd checked out - and this employee overheard us talking about it, and took our receipt over to the water section with us. He saw that there had been an expired sale tag left on the shelf, apologized, and walked us back to the counter where he cheerfully gave us the $2.40 back from the difference. Even though the deal was expired.
He didn't make us feel dumb or say anything snappish - just dealt with it professionally and with smile. I was so impressed.
Also I love the Sbux there - they're all great too.