Friendly staff, very good (not impeccable, but very good) service quality.
I recently had some service done to my ring at Readers. When I got it back, I noticed that one of my prongs was a bit off-center... though it's not something you'd notice unless you were looking for problems. I louped it and saw some uneven polishing, etc. -- BUT, this is only a problem under a loupe, I absolutely could not see any problem just my eyes.
I should disclaim that I am VERY picky when it comes to jewelry, and have really done my homework. The average person who isn't quite so nitpicky would be beyond thrilled with their service.
Their turnaround time was extremely fast. When I went in to drop off my ring, their service guy was out of town. He got to my ring first thing after returning and it was ready for me to pick up within 3 hours of opening that day (so it would have been a same-day repair had he been in when I dropped it off).
Overall, for even the most discriminating jewelry aficionado, I'd rate their quality of service as very good.
As a side note: park in the garage just north of Wilshire (on 4th). You get the two hours free, without any validation. Readers is just steps from the garage exit.