it reallly depends on the quality (not a circular answer). central europe is really REALLY rich in great wild mushrooms and has a long tradition of mushroom cookery (including and maybe especially boletes). but a great mushroom harvested in poland, shipped carelessly and stored too long will not be a good mushroom. you know what to look for -- firm, not slimy, stems should be firm, too. whether you want the caps tightly closed or not depends on how you're going to use them ... tightly closed is best for raw; open is a little sloppier but richer flavored ... best for cooking (trim the gills).