70's Black Sabbath is unbelieveably good. Sludge/stoner metal is a genre I can't get enough of, so this recommendation fell on happy ears!
The album starts off with the +7m30s musical journey of "Wheels of Confusion / The Straightener", which shows those pretentious prog-rockers exactly how this sort of thing is supposed to work. Following that is the far more straight forward verse/chorus/verse growl of "Tomorrow's Dream".
And then a ... piano and synthesized strings!? "Changes" is a beautiful departure from the general feel of the album, which is mirrored on the other end of the album by "Laguna Sunrise". Both offer a moment of calm, to catch your breath from all of the rock in between.
And then the album ushers you out, the same way it welcomed you in, which the medley of subtracks brought together in "Under the Sun / Every Day Comes and Goes"
For those that have never looked into Sabbath, or that might've been turned off to the band by tracks like "Crazy Train", I think "Vol. 4" is a much better album to form your opinion on.
Regardless, I appreciate the album both for what it is and for what it represents in the evolution of rock and metal. Super glad to see it on the list!