I am not a rock fan, so I won't complain about the lack of aggressiveness in the music of Brian Wilson and the Beach Boys like some other commentators do. I am simply interested in chord structures, instrumentation, vocal arrangements etc With those points in mind, this album can't be beaten!
In terms of chord structures, many of the songs are more complex to what the Beatles were doing in Rubber Soul, Revolver and Sergeant Pepper's (not to deny that these albums were masterworks too!). E.g Let's Go Away For Awhile, God Only Knows, Don't Talk. In terms of arrangements and production, this is, I believe, where classically influenced instrumentation was applied on a large scale for the first time - in a pop album (The Beatles would not do so until Pepper's and Abbey Road) - with splendind results. This was not your usual rock and roll, drums, guitars bass sound.
Even the lyrics are simple but honest.
Ignorant are those who think Elton John and Barry Manilow are superior to Brian Wilson's talents (this reviewer seems to forget that Elton John himself has said Wilson was one of his heroes). It is well known that many musicians and producers including McCartney and George Martin hold this album in high esteem (Leonard Bernstein thought highly of Wilson too, at least with regard to his work during the '66-67 years).
The album has also stood the test of time, and it sounds great in concert too!
So, I would suggest you purchase the album without considering the garbage of reviewers who dismiss it for the simple reason that they are musically illiterate!