Well if it was WOTLK everyone would use frost presence, but it looks like Blizzard is trying to get each spec to actually use the presence it is named after now.

Frost was better until this patch with the .5 GCD change to Unholy. Add the 5% haste from talents (that you pretty much take anyways for a filler) and it's now better for unholy than Frost presence is. Also to note, Unholy spec feels really good right now :) I'm loving what they've done to rune regen and how they're making your ghoul actually useful.

I'm kinda disappointed with the way presences are shaping up right now. As it stands, it looks like it will be as simple and straight forward as blood uses blood, frost uses frost and unholy uses unholy with very little deviation from that. It's a small step forward from the current situation but I was really hoping for more. If each spec just uses it's respective presence, why have the presences at all? Just bake those benefits into that spec somehow. Blizzard also seems to have changed their mind about allowing non-blood specs to tank easier stuff by just poping the right presence with out needing a bunch of defense gear because the crit reduction is tied to a deep blood talent and resilience wont't reduce crit chance anymore so if you want to be crit immune you have to have a tank spec.