While Dark Soul is active, your chance to trigger Nightfall is increased by 30%, Chaos Bolt and Shadowburn consume 20% less Embers, and abilities cost 30% less Demonic Fury.
Your Malefic Grasp and Drain Soul deal 5% more periodic damage, your Incinerate has a 8% chance to generate twice the normal Embers, and your Shadow Bolt and Soul Fire grant 5% more Demonic Fury.
I can't comment on the Destruction portion, since I simply haven't played the spec at 90 yet.
Affliction 2P certainly isn't strong enough to break T14 4P if you have it. It's fairly weak in my opinion. On the other hand, a 30% reduction on Demonic Fury abilities is pretty substantial. Touch of Chaos for a measly 28 Fury? Buy 3, get 1 free!
The 4P seems entirely unexciting all around. Static percent bonus damages usually aren't. I'm don't think the Affliction 5% on your channel spells would come close to matching the damage of well managed DoTs with the 1m20s CD Dark Soul T14 bonus. Still, it's better than the Demo side of things: 5% more Demonic Fury gained on Bolts n' Burns. Really? 5% of 25 (Shadow Bolt) and 30 (Soul Fire) is 1.25 and 1.5 respectively. I'm not sure if the game would round up the 1.5 to 2, but this would need to be brought up to 10% or even 15% bonus Fury for me to even begin caring. Better yet, let the 5% effect ALL Demonic Fury gains. Not just Bolts n' Burns. They're clearly trying to push us toward using a pet considering the Sacrifice nerfs and Demo buffs.
Let's say you got REALLY lucky getting back to back Soul Burn procs... enough for 30 of them. Without the bonus, you'd have 900 Demonic Fury. With it, you'd have 945. You could cast a single extra Soul Burn and nearly have the same amount with the bonus. By the time you're done casting all this crap, your CD on Dark Soul would have been back up and you'd be better off in Meta saving yourself 30% on those spell casts instead.
Edited by Kaboozey, 10 January 2013 - 03:15 PM.