What makes S.O.S. by Stratovarius notable?

'S.O.S.' is notable for its critical reception, often praised for its intricate songwriting and musicianship. The album helped to further establish Stratovarius as a leading force in the European power metal movement during the late '90s. Released on August 21, 1998, 'S.O.S.' was Stratovarius's fifth studio album, following the successful 'Visions'. At this point in their career, the band was solidifying their place within the power metal scene, building upon their previous successes while exploring more complex themes and arrangements.