In my humble opinion, a poor quality quilting fabric is one that is loosely woven (low thread count), feels coarse to the touch, or the dye continues to bleed and run after washing. Loosely woven fabric is often disguised by heavy sizing that washes out in the first wash, leaving you with "wimpy" fabric that is more difficult to sew and is even more difficult to "unsew." Beginners especially need quilting fabric that holds up well to "unsewing."
A good quality quilting fabric will have a higher thread count, be sturdier, more substantial, have a nice "hand," feel good to the touch and be more dye stable. If a print, it will have fine, sharp detailed printing. (Batiks are an exception. I expect the darker, deeper batiks, esp, in black, red, purple or blue to bleed. They are so gorgeous I work around that.)
In general, I have found that I can trust certain fabric manufacturers to produce good quality fabrics.
For instance, the Andover fabrics in the TQS BOM are excellent quilt fabrics. They are excellent quality, nicely printed, substantial weight fabrics that hold up well to any cutting and sewing errors I might have.
I have purchased both top quality fabrics and poor quality fabrics at quilt shops.
I have purchased both top quality fabrics and poor quality fabrics at JoAnns.
As a rule, quilt shops have better quality quilting fabric than chain stores like Joanns, but I have found some good quality quilting fabric at Joanns. Joanns carry lovely Kona cottons, which you can buy at a great price when they go on sale or if you use a coupon. They also have some low thread count, loosely woven, coarse fabrics at generally lower prices. You have to be careful. If in doubt, I would advise buying a small sample to test it by washing and sewing.
Happy sewing,
Judy