I guess it would depend on what your expectations are in batiks. I have some ... and not overly thrilled. There are so much better ( the designs with in the fabric). I was given a big box of them and found them to be a bit boring and not the "center piece" fabric. I will use them but in combination with other batiks.
As for the prewashing... never ..ever ...trust a batik not to run or bleed no matter who the manufacture is.