I'm sad to hear about so many bad experiences. I have one very close to my office (well my old office - new job as of Tuesday) and their customer service was always great. They always asked what you were making as they cut your fabric and even got used to seeing me and would ask how the last project went. I have to admit I went during the week, normally around noon or so and it was never very crowded.
I have another in a bit of a less desirable neighborhood that is always crowded on the weekends and I do what I can to avoid it at that time.
Over all, I have a feeling it has a lot to do with the management. Also, at the one I like, they automatically use the coupons on the most expensive item not on sale. Maybe I am lucky - but I have never had a problem.
Maybe you should just come to my Joanns in Milwaukee :)