Editing Warhammer 40,000/9th Edition Tactics/Dark Angels (section)

===Troops===

The Dark Angels don't have any unique Troop choices or anything that particularly stands out in 9th. What does matter is ''how'' you use your Troop units with their Chapter Tactics. 
* You gain +1 to hit rolls with units that have not moved, very much encouraging you to squat your units on an objective or in cover. 
* You automatically pass Combat Attrition Tests, so taking maximum-sized units isn't a huge deal with regards to morale.
* Fire Discipline means that if you survive the charge, you can make the enemy pay dearly when you have Tactical Doctrine active - You can shoot back at the enemy in the shooting phase with your rapid fire or assault weapons, hitting on a 5+. Quite funny when your dice are hot and you wipe an enemy unit off the board and off your objective - or when you charge on in and are stuck in combat with a big tarpit of a unit.

The best Troops depends on how well they synchronize with Grim Resolve. Which means their best use besides camping objectives is long range shooting. 
It's important to remember that Terminators and Bikes can gain Objective Secured, limiting the uses of troops if you just wanted them for taking the objective. 
So rather than a full tactical section for each, troops are ranked for their usefulness instead.

# Heavy Intercessors: Heavy Intercessors benefit from Grim Resolve and Bolter Discipline the most out any of the troop options. So unlike Codex Marines and supplements DA Heavy Intercessors are best used with the vanilla loadout of Heavy Bolt Rifles and good old Heavy Bolters. Arguments could be made though for the heavy options if you REALLY want your 42" shots.
# Intercessors: Stalker Bolter Intercessors have enough firepower sit on the objective and table what they shoot at. Grim Resolve allows them to shoot from the backline with little fear of retaliation. Also the only Primaris troops that benefit from a Repulser & should also be kitted out for long range sniping. Alternately, both the standard bolt rifle and auto-bolt rifle are viable options, allowing you to make Bolter Discipline and Grim Resolve, or maximize your Fire Discipline ability to allow you to be surprisingly decent on the assault and combines nicely with some stratagems. 
# Tactical Marines: The best use of Tacticals is giving them a heavy weapon. Take a Razorback instead of a Rhino and pick a Multi-Melta or another weapon that has a longer range. The Sergeant's Combi-Bolter should either be a Combi-Flamer or Combi-Plasma .
# Infiltrator Squad: The closest thing to the old Scouts. However since Grim Resolve and Bolter Discipline stack. Infiltrators end up being redundant. If for whatever reason you're running a Phobos heavy list, these guys can actually get rather nasty. Fire Discipline applies to them, and Marksman Bolt Carbines autowound on sixes. Combine that with the comms array for rerolling 1's, and anything within 24" is going to be eating a lot of bolter shots every turn.
# Incursor Squad: Has the same problem as Infiltrators. While Occulus bolt carbines stack with both Grim Resolve and Bolter Discipline and get rerolls with their Paired Combat Blades. They are still inferior to both Deathwing Knights, Ravenwing Black Knights and DW Terminators with Thunder Hammer & Storm Shield Combos. Alternate take, they're ideal for taking objectives and being hard to shift. Fire Discipline applies to them!
# Assault Intercessors: Same problem as Infiltrator and Incursor as they are lacking compared to Objective Secured Termis and Ravenwing. They may get more chances to reroll however Chainswords are not that great compared to Power Fist variants and the pain Deathwing Knights can inflict. Don't take them.