Feel it, baby! Ewww, that sounds bad, but you know what I mean. Touch and you'll learn. And even a few of those with a nice "hand" might wash funny. Most will wash and wear beautifully.
If you're buying online, stick with brand names. Still, Wile e Coyote's Acme products (the lesser brands) will sew and wear quite fine. Perfect for stuff that won't be washed a lot or placed in a museum. Save your fabric dollars for heirloom quilts or those dang cute collections they keep releasing! ;) Somebody make them stop!