Musical historians condemn this album as something worse than the plague. I think part of the reason for that, beyond their dislike of the music on this album, comes from all the upheavals Chicago went through during the recording of this album. The tragic accidental suicide of their singer guitarist, the dropping of the roman numerals for a straightforward album title, showing the band members on the cover, breaking away from their long time producer and so on.
I personally think this is a pretty groovy album. I like the time period (I'm a fan of the 1970's in popular culture), I enjoy the mood of the album, which is slick, but also quite sombre. It's an adult album, like Chicago albums usually are. It might not be as inovative as earlier stuff, but it's a solid piece by real professionals.
Like I said in my title, this is a good album to just kick back and listen to. Close your eyes and relax after a long day at work, have a cold or warm beverage and just let the music wash over you.