Demo has more mobility now since most of Aff's dps is tied down to MG and DS. Though on a stand still straight dps target aff will do more dps regardless, until people get more raid geared demo seems to just be better due to boss mechanics.
I really would go with demonology right now, it's better for AoE, I feel it has more tools for non ideal fight situations. Affli may be better on simcraft patchwerk but really I have yet to see it pull ahead in reality; it relies way too much on that kind of fight (low movement, one target, high health) whereas demonology is just more versatile.
And its also more fun imo than micromanaging dots, but that's subjective.
Affliction is great for pretty much every fight in Mogushon. (We've gotten through the transition at 85% on Elegon tonight and almost to the 50% transition cleanly)
I definitely think whatever spec you're personally best at will give you the best results, but affliction is very strong in this first raid.
I would like to ask about the garajal - do your dots wear off while u jump into the spirit realm immediately? Or tick off till the end?
Another question is - the Stone guards - ain't it too punishing to spend GCDs or SS/SW to place/refresh dots on one of the doggys just before it starts to cast its petrification? Is it viable to dot the Dog that is solo-tanked (i.e. receives a 90% dmg reduction)?