WordNet sense 1 (based on or told of in traditional stories; lacking factual basis or historical validity):

mythic, mythical, mythological, mythologic

WordNet sense 2 (lacking in reality or substance or genuineness; not corresponding to acknowledged facts or criteria):

unreal

WordNet sense 3 (extremely pleasing):

fab

WordNet sense 4 (giving pleasure and satisfaction):

pleasing

WordNet sense 5 (beyond belief or understanding):

incredible, unbelievable