The poll.
I noticed some people still sometimes ask which faction they should choose, while since AoM’s release I mostly make a choice based on RP reasons or even on a whim. Before AoM I could make use of some level 70 faction pieces and augments, now I don’t even consider their augments that much.
Personally I don’t mind this and even think it’s cool, just wonder if it would be fair to answer people that it doesn’t matter what they choose.
Maybe at the beginning during everyone’s first playthrough there was a moral dilema (apart from those special kind…Cough’thon 
- no disrespect, honest), but imo later on it’s all down to “which faction’s augs benefit my <insert build here> the best way possible”. Said can be said later on with AoM and befriending cannibals…
Kymon’s has some nice faction stuff, slightly better than ODV I think, but overall I would say gameplay-wise it’s six of one and half a dozen of the other until you reach Nemesis with the faction you shunned. Then Iron Maiden comes into play and she’s definitely the harder Nemesis between her and Zant. Still, it takes so long to get to Nemesis with either KC or ODV anyway that you’re likely to complete Ultimate without seeing their nemesis spawns unless you grind hard.
Generally, I don’t find there to be much reason to use either’s augments. But every once in a while, I will use one, or wish I could use one from the faction I did not choose. The problem is that I don’t figure out my final gear choices until I hit level 94, so I never know until I get there.
I honestly think most of their Revered tier augments (and maybe the Honored tier as well) could use a buff/rebalance, so that the choice becomes more impactful at higher levels.
With AoM, they stayed sort of… left behind with the other non-AoM factions, and that kinda sucks.
EDIT: I’d love to see these two factions have some weapon/off-hand augments as well.
Most people would choose anyone, then choose the other one on next difficulty so they can get all of those factions’ items.
I myself, did some role-playing such as, being a saviour as a Kymon’s Chosen and save all save-able npcs. And, being a deathbringer as a Death’s Vigil and kill all npcs.
Though, at ultimate difficulty, you should choose wisely. Save npcs that would be able to be fought later and kill all farmable npcs.
Some tips for ultimate difficulty “perfect run”:
1. Let the madman at Burrwitch village live.
2. Let Direni go. You’ll kill him later.
3. Prevent a man who is going to burn his family by taking them to Devil’s Crossing.
4. Save Isaiah Reddan.
5. Save the people at New Harbour by paying money.
6. Destroy a large crystal behind Cronley’s boss area.
7. Tell the man at John Bourbon’s room at Devil’s Crossing to not chase after Elsa.
8. Kill the demon child at south-west area of Infested Farm.
9. Save the witch at Blood Grove.
10. Kill Anasteria.
11. Kill Larria.
12. Kill Ugdall.
13. Fight Ulgrim.
14. Save Bloodsworn captives.
15. Save Nicoh.
16. Save Hagarond.
Ey
I side with The Order all the time except for few profiles where I make evil choices to farm other stuff.
The only Evil Choice made during my good playthroughs would be siding with Scorv (the choice is reversed on my evil playthroughs where I kill him)
I still say Nomedia (or whatever that thing in the cellar is called) needs its own MI
With new augments from Malmouth and Coven it hardly matters anymore. Order has couple of pretty neat augments: one for rings/amulets that gives cold damage/da/bleeding resist and one for gear that gives 7% aether/10% lightning (last one is super relevant for a lot of build that play crucible). Kymon got decent 12% chaos resist ring/amulet augment and some find use for its 7/7 vitality/chaos resist gear augment.
But overall Order’s playthrough is more fun. The whole “Oh shit we didn’t know what to do so we randomly chose an ancient primordial God as our ally and now it seems like he is going to own us” shtick that Kymon’s is a bit lame.