The consensus seems to be that this was a naive first try at classical music and superceded by his later stuff qv Standing Stone.
Actually, when I want some classical McCartney, this is invariably the one I turn to, and turn to with pleasure.
Yes, there are weak points, but there are some stand out moments: "Non nobis solum..." at the start, a genuinely powerful cri de coeur in "Father", the violin solo in "Work", "The World You are Coming Into", and the cheery "Let's Find Ourselves A Little Hostelry" sung by Willard White.
You also get the feeling that there is a lot of the real McCartney in the lyrics: the paean to "Family" at the end. And ultimately, I reckon that sums it up for quite a lot of English people.
This is the most performed McCartney classical work and I don't think that's coincidence: it has got a lot of sweet melodies and it tells a story that you can respond to, even if it isn't the deepest set of lyrics ever.
Carl Davis - at the poppier end of classical - did a really good job, I reckon, putting it all together.
Buy it, especially at £9.99 and enjoy.