"Sum Of R's sound shifts from doomed cinematic guitar descends to electric guitar music box-ism meets death tolling and the shimmering of 50's sci-fi rise and ebb". (Musique Machine) "Sum Of R don't really trying to oblige to specific genre but leaning on the mood and the expression of their output. You hear some SunnO))) riffs coming from the back, but then it becomes a post-apocalyptic Canadian post-rock, moves into the minor dark-ambient of the likes of Xela and The Fun Years." (Hair Entertainment) "The clock goes crazy, the sounds seem to flow forward and backwards at the same time. The sound sources merge into one another and silver vibrations create black whirls." (Bad Alchemy) "If your reference for guitar noise sound are Sunn 0))), well, with Sum Of R be ready for something different: if Sunn 0))) base their sound on bass frequencies growling guitars, Sum Of R make their guitars sound like a organ mixed using a vacuum cleaner and then they add to it effects and other instruments". (Chain D.L.K) "Sum Of R's sound sit's in an heady and atmospheric place between doom metallic's, guitar drone craft, filmatic post-rock scaping, grim 'n' glighty ambience and general atmospheric dwell and unfold". (Echoes)