‘It is Sweeney’s Third String Quartet, from 2004, that has the word masterpiece stamped all over it. It is a monster of a piece lasting 36 minutes. It’s totally abstract, and some might think it discontinuous, with its apparently fractured progression, pounding rhythmic unisons that dissolve, seemingly isolated and unrelated musical events, wild dances, and melancholic intensity. With a little familiarity, the events begin to cohere, and what emerges is a kaleidoscopic piece of a rare conciseness and almost Beethovenian intensity’. (Michael Tumelty, The Herald, 2007). "Gabhail a Chreig (Taking the Rock)" – ‘contrasting elements of rhythm against lyrical writing are condensed into the single movement of Sweeney’s piece. There, they alternate, punctuating and shaping the music until, with astonishing brilliance, they are revealed to be all part of a single idea.’ (Alan Cooper, The Herald, 2007). ‘I close this brief survey of a very remarkable composer with another MacDiarmid setting ‘in a tiny choral song, "The Innumerable Christ", Sweeney reaches out with his modes and metrics in a folksong-like simplicity that literally encompasses the universe. It took its first hearers’ breath away.’ (Jamie Reid-Baxter, Tempo, 1994). ‘Sweeney has always been a thoughtful, politically engaged artist. In "an seachnadh? (The Avoiding)", just as in "Hallaig" three years ago (Sweeney’s profound meditation for organ on Sorley MacLean’s elegy), he emerges as a first-rate composer, who urgently addresses, and achieves truthful utterance through the ‘matter of Scotland.’ "An seachnadh" is a masterpiece’.’ (Neil Mackay, Tempo, 1994).