As prog albums go, I am not that impressed with it from a musicianship perspective. It was quite innovative with the sounds incorporated and the interesting compositions. I find Pink Floyd in general to sound very "samey" from album to album (starting with Meddle...before that they were all over the place) and I grew kind of board with that sound.
Initially I was not very impressed with the album either (I always thought more of Wish You Were Here), now I am. The compositions are splendid and quite unique. Yes, in terms of technical musicianship there is better playing in prog, but that's not the point for me.
I disagree that Pink Floyd sounds "same" from album to album after Meddle. You can't seriously state that when comparing Dark Side with The Wall (another masterpiece), for example.