I made a thread about this a while ago, but the choice is hard for me because I'm comparing things that aren't really comparable. I wonder if the majority of players on this site have a go-to pillar of the game that makes their decision easier, or if you're more like me and multiple aspects are important and you have to weigh it out. These are the major categories I can think of but please elaborate in the thread about your choice!
Story and Theme
Choose this if you're mostly picking based on the continuation of the story and theme of the covenant.
Cosmetics and Aesthetic
Choose this if you're mostly after the mount, armor sets, weapon skins or other cosmetic goodies the covenant offers.
Fun Ability Kit
Choose this if you're mostly having fun with their ability kit and you want mechanics that are enjoyable to you.
Min-Max DPS and Performance
Choose this if you're mostly looking at the math and if you're concerned about performance in PVE/PVP content.
Tough Call
Choose this if 2 or more of the above pillars are pretty equal to you and you're having to really think about it.
BTW mostly liking one pillar doesn't mean your choice isn't hard. You could only really care about cosmetics and it could be a toss up for you if you want the Necrolord weapons or Venthyr weapons for example. What I want to explore in this thread is if you really like the mechanics of Covenant A, but really like the cosmetics of Covenant B... and you're dealing with a tough choice because both of those different things are important to you but also hard to really compare.