Infraction: 7. Do not beg for hand-holding.
Message to User:
As VoidStar said in the post you're quoting, you're not giving enough info to go on. Using his post as a template you should be able to figure out the answer on your own. On top of that, a good raid leader should be figuring out the buff situation on the fly. And on top of that, a good raid leader should know demonology is amazing for AOE fights, but not much else. Sounds like you've got a lot to take up with your raid, and not much to contribute here.
TL;DR - It's almost certainly better for the raid for you to be Demo.
This used to come up a lot in discussions, but frankly the answer to "is 10% vs. 6% spellpower worth more than another spec" is now very obvious and very clear from even a cursory consideration of the sim results. There are other related questions such as "should I bring an elemental shaman or a demo warlock?" or "I have several warlocks, which should go demo?" that have much less clear-cut answers, but that's not what you asked so I assume that those aren't options.
Firstly, precise stat weights can only be direclty applied to very specific circumstances (the ones for which they were generated) thus making generating precise stat weights for an entire raid essentially impossible, or at least hopelessly specific. As such one cannot "know just exactly how much 1 point of spell power helps particular classes/specs". It's generally not especially useful to do so anyway because it's the relative worth of stats that is generally important when making gear choices, but I digress.
Generally speaking, however, Spellpower is (I believe) simmed as the second best throughput stat for all casting classes (behind only Intellect). Thus, the answer to how much it helps is: "a lot". Do not forget that the effect that the spellpower has on healers is also important, but rather challenging to weigh against the personal dps gain that a non-Demonology spec might conceivably bring you.
However, the theoretical difference between the different Warlock specs is now so small that it currently sims better for you to be demo if you're the only source of the buff even if you're the only caster in the raid.
If you want some numbers, let's ignore a swathe of dangerous assumptions and use some from the Simcraft thread. You are either the 359 demo from the simcraft thread, or the best 359 in those results: Destruction. You do 23863dps in demo and you do 24304dps as the destro warlock before we take off the spellpower buff. Spellpower simmed as being worth 2.3013dps per point and you had 8597 of it when raid buffed. Losing the buff would lose you 313 spellpower, thus a loss of 719 dps, putting you at 23585dps, which is less than the demo spec. Remember: this doesn't even consider everyone else in the raid. The numbers shouldn't really be used this way, but it serves to illustrate that the buff is worth orders of magnitude more to the raid than the difference in your spec.
Now, your raid might be better served by someone else going demo, or someone else bringing an elemental shaman or many other options that only you can know or decide about, but to raid in another spec and go without a 10% spellpower buff at all is, in my opinion, doing yourself and your raid a grave disservice.
As an aside: I am astonished to hear that your fellow raiders would complain about you choosing to buff them at what they perceive to be your own expense!
They complain because they want to see higher dps numbers from me, I mean demon is pulling decent dps, but not the best. I'm coming in 4th or 5th alot-I am undergeared a bit still (still need 2% to get hit capped), but they seem to think its spec choice thats causing the drop off.
I tried to explain that the 10% SP (assuming no other buffer available) buff is more important, but they discount it, saying its only a minor dps buff for everyone at best. We have an enhancement shammy and a spriest in our raid so at least two dpsers are getting the sp benefit. I always felt that the 10% boost was the clear choice since we don't have the buff, but I didn't know the simcraft to back it up and I didn't know that its better even if I'm the ONly caster in the raid. Thanks for the numbers!
So, you touched on this but I was a little confused, is the 4% buff worth it? Is the 4% difference the numbers you were referencing? 313 spellpower seemed to be around 4% but I wasn't clear if you were saying the 10% or 4%, sorry..
just to clarify lets say you have a mage in the group or an elem shammy, would it still be beneficial to go demon for just that 4% boost? Your discussion above seems to indicate yes. Theres so little difference between the simmed specs that even the 4% boost is still worth it (Remembering that since you'd have a mage or elem shammy you have to assume at least one other person is getting the 4% buff as well plus whatever the healers get for it).