I've had trouble killing T3 hordes (like eveyone else I assume) and I thought I'd try killing them in close combat with this list. It expects to face either IG or marines in a competitive setting.
The premise is that a unit of Incubi with Demiklaives will deliver 7.83 wounds or about equivalent to 35 splinter shots vs. GEQ (more from turn 3 on), while also doing well vs MEQ, and being highly mobile and pretty resilient when in transports. Demiklaives seem worth it for this use since 48 pts of them buys you 3.5 dead guardsmen per turn on average. So Incubi kitted this way are way more economically efficient than cannonborn or scourges in this use. 10 basic kabalites firing rapid fire and then charging would be 4.44 + 2.44 wounds so they are more points efficient but you would need more transports for them. 5 kabalites firing rapid fire in a twin splinter cannon venom firing rapid fire would be slightly less damage for a slightly higher price with more survivability, but less utility vs other targets.
-- HQ (80p)
Haemonculus, Crucible of Malediction, Venom Blade (slightly more efficient vs GEQ, should probably be Agonizer really)
-- Elites (590p)
4x Incubi, Klaivex, Demiklaives x 6
-- Heavy Support (300p)
Reaper x 2
-- Flyer (194p)
Voidraven, Dark Scythes, Voidraven missiles
-- Dedicated Transport (346p)
Raider, Dark Lance, Shock Prow x 1
Raider, Dark Lance x 2
The goal here is to have enough can-opener firepower to be able to probably kill a stormraven or a tank T1 so that means at least 8-10 lance type weapons, preferably more. Here we have 10 since dark scythes count as about 1 lance a piece. Voidraven was chosen mainly as a points sink, I think it's not that much better than a 2 DL RWJF (it will typically do 0.56 more damage to a vehicle without using the bomb). But it has less low-rolling potential and this list only has 4 command points which I will let the reapers have. Typically I would prefer RWJF w/dissies but this list already can kill MEQ and will struggle more vs armour.
Haemy sits back and buffs the vehicles in case we don't go first. Raiders move in. Reapers reap from backfield. T2 we charge and hopefully kill a lot of dudes, and live to fight again.