NOW is usually pretty reliable. They seem to pass their testing on consumerlab whenever I look up a product. Their astragalus hasn't been tested there though so I can't speak for that one.
I've always trusted NOW brand. After what Dante mentioned, I think it makes more sense to not use their astragalus in particular, more so knowing that Vitamin Shoppe astragalus works so well, but I do think I'll continue to use a few of their other products.