I think we had some discussion recently about DIO and this one was nearly unanimously hailed as the band's worst.
While I can agree that it may rank near the bottom of the band's catalog, I certainly don't think it's a bad album.
The album has an overall dark, raw feel...almost sounds like a live recording. The instruments are big & clear sounding and RJD's vocals are superb (as always).
I know some have made the statement that they don't think Tracy G was a suitable guitarist for DIO. I definitely don't agree. 'Strange Highways', regarded as an "underrated" album by many DIO fans, was also a Tracy G performance. The songs on that one were very heavy...some of the heaviest in RJD's career next to his work with Black Sabbath...and are also some of DIO's most intense moments.
'Angry Machines' has a little bit of experimentation (most notably the songs "Black" & "Double Monday", which are very unlike past DIO material), but overall continues on that dark, Sabbath-inspired material on 'Strange Highways'. Songs like "Institutional Man", "Hunter Of The Heart", "Stay Out Of My Mind" & "Golden Rule" are certainly on par with DIO's prior level of quality.
Again, I can see it ranking near the bottom of a stellar catalog, but that doesn't make it a bad album by any stretch.