I don't think Saga Symphony is ideal for a first stab at Leifs' uncivilised oeuvre. Newcomers should try Osmo Vanska's other disc, which boasts the sublime prelude Geysir and heartstopping Consolation for string.
Saga Symphony is most uncompromising, starting as it does with Skarp Hedinn, the first of five character portraits, whose music is especially violent. A relentless series of body blows. Leifs' unique gift for lyricism, for identifying just the right kind of sonority to suggest the uncanny or the humorous, can then be heard in the succeeding portraits: Gudrun Osvirsdottir (adagio), Bjorn & Kari (scherzo),Glam & Grettir (intermezzo) and finally the warrior-poet žormóšr Kolbrúnarskáld.
You must jettison as many preconceptions as possible and let your mind open to imagine these bold individuals in the wild frontier that was their adopted homeland. Think of Skarp skidding off the glacier to attack his man, or Kari seeking redress for the killing of Njal and his family. Think of Grettir acting as bait for the reanimated Glam, the two then careering about the house, crashing through the front wall into the moonlight. Think of Gudrun, stoically enduring the loss of husband after husband to unnatural deaths. At a time of world war, a vicious army of demented Germans having perverted their own culture and ridden roughshod over most of europe, Leifs looked to his country's literature and sought to conjure the spirits of indomitable warriors to face down the forces of tyranny and racial intolerance. Think of him, trapped in the heartland of the aggressor, unarmed and still unable to escape (the Leifs family finally got out in 1944). Shostakovich wrote his music 'for the drawer', and Leifs wrote his.
As always, the Iceland Symphony and Bis collaborate to produce superb, dynamic, crystal clear sound. Raw, dissonant, but still poetic and not without moments of repose. If you care about the symphony then Leifs' Symphony No.1 (Saga Heroes) should be on your list for investigation.