Deadly catalyst Disk, is it good?

I miss the old disc (forget the name) that also paired with this disc that inflicted Armor Shred and...some other debuff. Agreed that this is the best purple disc if you get ruthless swiftness (I also like to use ruthless offense, it stacks up faster than the 5% offense for buffs disc if you have the Deadly Catalyst disc, but maybe that's just because my toons are undergeared so I have to have that damage boost to make progress).