I get great service from ONE particular clerk at Joann's. She helped me figure out the yardage I needed as we went through the fabric I had chosen as she cut (it was difficult since I had a pattern for a baby quilt and different material and colors!). Well, I should say SHE figured out the yardage and it took quite a bit of time. Thank heaven they weren't busy at that time.
One thing I don't like about Joann's is that a lot of the time I can't use the coupons because the fabric is already on sale.
That said, the nearest LQS I frequent is about the same in some regards. There are some clerks that will help with anything and sometimes I go in and never get a glance by anyone. No coupons, high prices but great fabric and thread. They carry thread Joann's doesn't.
I think it just depends on my mood, their mood and the day!