Well, picked up the codex today, and I am fairly impressed by it. The Lion's Blade Strike Force can make for a very durable gun-line against assault armies thanks to Supreme Fire Discipline, a rule that further improves upon what Grim Resolve does for Overwatch.
The inclusion of Grav weaponry is nice to see as well. Initially, I was disappointed to see that they folded the Sacred Standards back into a single entry, and that the unit that will get the most use out of it is your bog standard Command Squad. Granted, taking 5 Grav-guns + the Sacred Standard in a drop pod is getting a mobile grav unit that the Dark Angels would not other wise have, seeing as there are no Centurions in the codex.
Three point drop to the Deathwing is nice, considering they have gotten better. Ravenwing bikers received a 2pt drop in cost, and despite still being restricted to 6 bikes in a squad, have become more durable when Jinking. Oh, and dedicated Attack Bike Squads! Yay!
The Darkshroud is a must have for any army that is considering assaulting. Just absolutely necessary with the improvement to the Icon of Old Caliban for no additional cost.
The flyers effectiveness has increased exponentially. For the Nephilim, the Blacksword Missiles increased in Strength and AP, it dropped 10pts, and so far hasn't had Missile Lock FAQ'd away. The Dark Talon... holy beslubber do I want one. The rift cannon hits like a Demolisher Cannon with the potential to be a Vortex weapon. The Stasis bomb pretty much guarantees that you can wipe a unit from the table.
The formations are pretty cool as well. The Demi-Company increases the bonus for Overwatch granted by Grim Resolve, but not quite to the extent of the Lion's Blade. The Ravenwing Attack Squadron has so much synergy with the Deathwing and with models in it's own formation. The Ravenwing Support Squadron has gone full Tau on us when it comes to Overwatch. I think the two coolest formations though are the Ravenwing Silence Squadron, which is a pair of Nephilim and a Dark Talon that guarantee a hit with the Stasis bomb; and the Hammer of Caliban, a formation that puts a Land Raider of any variant into a vehicle squadron... like three Vindicators.
The Interromancy discipline is actually pretty interesting, althought it is disconcerting that the #6 power is Warp Charge 3, but it has the potential for its effects to be permanent.
The Tactical objectives are fitting for the Dark Angels, with an added bonus being that if you draw one of the 6 Dark Angel objectives, you keep it secret from your opponent until you achieve the objective.
Overall, I am happy with the codex and can't wait to get a game in with it on Thursday.