SoV or SoR for tanking

I was reading the PTR patch notes for pallies, and Vengeance seems to be getting a bit of a buff next patch. "Seal of Vengeance duration increased to 15 seconds. In addition, when Seal of Vengeance strikes a target that already has 5 applications you will cause instant Holy damage."

http://worldofwarcraft.com/patchnotes/test-realm-patchnotes.html

Granted, it's not as dependable as SoR, but does an increased duration of time for a chance to re-proc, and the damage bonus for having it proc on 5 stacks make it significant of an increase in damage to use regularly on boss mobs? I've personally have used SoV pretty regularly on boss mobs, and have been able to keep it up pretty easily, and have noticed an increase in my threat over SoR. Maybe it's all in my head. Thoughts?

There was some discussion about this in another thread somewhere, lemme see if I can dig it up...

I think this is the one: http://www.failsafedesign.com/maintankadin/viewtopic.php?t=1206
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