Not necessarily. The movie is scored by Michael Giacchino, who has won numerous awards for his original scores. His body of work includes numerous Pixar films, Jurassic World, the new Star Treks, Rogue One and plenty more. He's currently the go-to guy for blockbuster movie music these days.
Reviews are starting to filter through. Overwhelmingly positive - 98% on RT from 41 reviews and 74 on metacritic from 15. They all say the plot is pretty formulaic, Mikkelsen is the latest in a long line of forgettable marvel villains (but he's one of the better ones) and that Rachel mcadams is pretty well non-existant in the film, but that Cumberbatch is perfect as Strange, the visuals and sound are fantastic and that the humour works well.