This is actually a good choice for zerging before homam legs. There is little good replacement for homam legs for zerging but replacing this with gloom can garner you a good chunk of HP and acc (SH+1, for e.g, Homam body, etc).
So, definitely pick it up if you don't have homam legs yet.
If you understand how DRK Souleater Blood Weapon zerging actually works, then this is a great piece for anyone who doesn't have Homam pants yet. If you don't have a good haste+%/HP build and a zerging weapon, work on those before getting these.
gloom breastplate isnt hard to get, 4-5 people can easily subligar farm in sacrarium.
now with the shantotto add-on you can get haste +3 on the pants which is much easier to get then homam but to be honest if your building a zerg drk set you probably have homam already.
These are still useful once you have Homam legs if you are zerging with a 2 handed weapon now the haste cap is 80%.
Assuming you have SV March x2 and haste to cap magic haste (43.75% haste)
And you have 5/5 Desperate bows (or 3/5 + Hasso) you will have capped 'JA Haste' @ 25%.
This means you only need 11-12% haste to reach the global haste cap (80%).
Turban 5%
Homam feet 3%
Homam Hands/Dusk hand 3%
Total 11%
This allows you to be more creative with your HP. Some people use these legs combined with Homam body for a few more HP (and more Accuracy) than the normal Gloom + Homam legs combination.
Despite all of this, any multi hit 1 handed weapon will normally out parse a 2 hander in a DRK zerg.
"Enhances 'Souleater' effect" bumps the 10% HP->Damage effect to 12%. 12% is cap, so this will not stack with Gloom Breastplate or any other Souleater gear.
That said, for zerging, Gloom Breastplate beats these because you're not using up a haste slot.