Got a Khorne Lord of Skulls recently, and I must say first of all props to GW for such an awesome kit. Now about the KLoS, so far i have had great success with it. The 2000 pt list I have been running so far is:
KLoS, Daemongore cannon, Hades Gatling Cannon.
Chaos lord, Axe of Khorne, Bolt Pistol, Sigil of Corruption, Blood Forged Armor.
19 Bloodletters, Champion
KLoS is a powerhouse both shooting and ranged rivaling most anything else in CC and shooting.
KLoS and Heldrakes have complete board control with the flamers.
Enough OS units to win objective based games.
Bloodletters can deepstrike on objectives later game.
The big unit of bloodletters looks threatening and draws enemy fire.
The KLoS is also a demoralising models to see on the table against your army.
If the KLoS dies the army starts to crumble
KLoS is really expensive
You can't make any mistakes with this army without catastrophic results
If the heldrakes come in separately it is easier to deal with them.
All that being said my list so far hasn't lost and more surprisingly the KLos hasn't died, he is always left with 1 or two HP at turn 6 or 7.