Well, Vigilus has a formation that lets all ravenwing units in it +1 to hit (i think) against a unit that has already been wounded by something from the formation and a new warlord trait ( my friend has borrowed this book and i cant remember what this does) along with i think a new relic.
and thats about it.
PA ritual of the damned has:___
Vanguard primaris units, rules, psychic powers
New primaris deathwing character (though the points are on the website for this model because
GW forgot to put them in the book.
Updated points values.
Many MANY new strats for ravenwing and deathwing such as the one that allows
DW units to arrive from reinforcement anywhere outside of 6" of an enemy providing they are within 6" of a ravenwing unit. Also a very fun one that lets landspeeders spot targets for whirlwinds
New warlord traits and relics (too many of these to list but im sure you can find them somewhere on here, possibly in the old news and rumor thread for the book or the
DA tactica.
Most importantly though is the DOCTRINES. Just like normal marines we now have various effects depending on what turn it is and we also have our very own special doctrine too
Chaplain rework. Our chaplains now get their special litany prayers which are varied, and our own chapter specific one too.
When the normal marine book was redone last year they gained a LOT of powerful new stuff, and the non-codex chapters fell far behind. the
PA books have now meant that
DA,
BA and
SW have caught up (at least mostly) as without these upgrades all 3 were amongst the worst armies in the game.
Overall this book is an important update to the codex. If you want to know more,
id check the
DA threads as suggested as there really is an awful lot of stuff in the book (some ork stuff too, but vast majority of the book is all about updating the dark angels codex in line with the new marine stuff.
I was about to get a copy (
id just bought the nid one and was working through my armies book by book, when this global situation happened, so i dont have it myself yet.
Hope this helps.