This is a subject that has been on my mind lately as well. I often receive donations of fabric for our local Project Linus, and as the resident quilter, it's my fun job (truly!) to go through it. When I've pulled appropriate fabric, I wash it and iron it.
I can't tell you how many times I've found something pretty, only to find upon ironing that it's not cotton, or found something terrible (either rough or see through or falling apart in threads) only to find it's a major name brand fabric. It's not unusual for me to get fabric from the 1990's, so I've really been able to compare fabric and brands over the years.
And what I've found? There is good fabric and bad fabric, from all brands, all stores, all time periods, all manufacturers. That's why I base my fabric choices on the fabric in my hand, regardless of where it came from.
And to be honest, I love fabric so much, I don't turn much away...