G.N. Piette is right in his review. This is a superb album and an awesome achievement. I bought it when it first appeared and it sounds every bit as great now as it did then.
Keith Emerson's Piano Concerto is an excellent piece of composing. Lake's and Palmer's sides I find mixed, but both have plenty of great moments nevertheless. And the two group pieces that made up the original fourth side are as fine as anything ELP produced during their dazzling and groundbreaking career. Fanfare For The Common Man has become pretty much legendary - and Aaron Copeland himself praised what the band had done with his composition. Pirates is a superb mix of rock band and orchestra. On that technical level it's a real achivement, but as a song it's full of really strong music and very evocative and powerful lyric writing.
ELP were massive in the seventies, and from this album it's clear why that was. Their skilled blending of rock and classical reached a peak here, and they proved themselves equally masters of both genres.