As it is right now, Demonology is 4th, providing a powerful buff and having a very simple rotation, but not yielding very high personal DPS. The less personal DPS is compensated in a 25-man raid, especially if it's caster-heavy. Affliction comes next, requiring hefty amounts of Haste to gain extra ticks on its DoTs - more haste > more DoTs > more Nightfall and Eradication procs > more DPS. Destruction and Demo/Destro hybrid are considered close, with Destruction generally having higher DPS, but hybrid pulling ahead significantly on Decimation phase. All of the bottom-tier talents in Destruction are very strong, but the Soulfire spam is just broken, combined with some Destruction talents and Hybrid being able to double-dip from the 2-piece Tier 7 bonus.
That's pretty much everything you need to know about low-gear Warlocks.
Can you please tell what glyphs to use with that Hybrid spec ?
Conflagrate, Imp and Immolation. Conflagrate is the natural first choice, Imp is very strong in hybrid because of the bonuses it gets from both trees, and Immolation goes last, comparable with Incinerate. The reason you don't pick Incinerate instead is because you don't use it in Decimation phase.