I've been a huge fan of Avenged Sevenfold as far back as Waking the Fallen, even as a kid. This is, in comparison, a much more tame album put beside WtF and Sounding the Seventh Trumpet, at least melodically.
The main problem with the music is the language. The f bomb isn't the most common of words, but it's present. The lyrical content (sexual, for example) is most notably found in The Beast and the Harlot. However, being as this is referenced very closely to the Bible, isn't a problem, as banning the album for that reason might as well be banning the bible.
As for the positive messages, if taken loosely, they can be found loosely in songs like "Betrayed," where the band memorializes the late "Dimebag" Darrell. Another song, arguably their largest, is "Bat Country," where the band speaks against the lavish, indulging lifestyle of drinking and sex. Of course, the references are more implied then said explicitly, so, once again, it isn't a problem.
Language is the only issue. Great album,