I really think it depends on the store. I had one by my old office that was great, one my my mothers house (between offfice and home) and it was not as good but ok. There is another (I know I am lucky!) about 20 minutes north of me and the people are just ok. Lines are always very long - but I am also there on the weekends.
Overall - I usually plan a while at Joannes since I wonder quite a bit. So the wait in line is kind of expected when I get there.