My DK is nearing 80 and I'm sitting down and trying to work out my target gear set (this decision will affect what I spend some of my dungeon acquired badges on).

I can see two options I can go for:
4P9 Gear Set
Faceplate of the Honorbound
Thassarian's Chestguard of Conquest
Thassarian's Pauldrons of Conquest
Thassarian's Legguards of Conquest
Thassarian's Handguards of Conquest

2P9 Gear Set
Faceplate of the Honorbound
Breastplate of the White Knight
Shoulderplates of Enduring Order
Thassarian's Legguards of Conquest
Thassarian's Handguards of Conquest

The latter set gives me more stamina / armour, but at the expense of the 4 piece bonus. As an Unholy Tank, Bone Shield is a fairly significant part of my survivability (though currently I haven't learned to use it as much as I perhaps should).

Is the higher EH worth missing out on the 10 second cooldown reduction?