Don't get NLB! Voidfang vestments are a good Crucible item and are useful to both classes due to the grenade energy on respawn. A voidwalker with the axion bolt grenade can make the most out this perk though. For most PvE situations they are outclassed by some other exotics, but in the Crucible they work just fine.

Out of the choices, I recommend getting the chest engram first, and then, if you don't get a good chest from that, go with what you want most. Voidfang Vestments is really good, though. I recommend it as well.

It's far from being the best exotic piece of gear you can have for your Warlock. There are far better exotic items for a Warlock, like the Obsidian Mind, Apotheosis Veil, Start-fire Protocol or the chicken feet gauntlets. So maybe save your coins for something more useful. No Land Beyond is a joke, it only worths the coins if you want it's grimoire card and a exotic shard.

I'm having the same dilemma. I'm probably gonna get it since I don't have it yet but that's 65 less heavy ammo I can buy and who knows when xur will have heavy ammo again.

If your playing void walker more often then sun singer it helps a lot with axion bolts. Also it looks amazing with glowhoo 😍