WHFB: Marked Men in 8th.

We basically have a year of playing 8th Edition under our belts and I think it's time to take a look at some things and how they are working out.  Having spent most of the past year playing my WoC in friendly and tournament games, I want to take a look at the Marks and how they stack up in 8th.

Undivided:  Although no longer an 'official' Mark, units and characters that are not sporting one of the Dark God's personal brands are classified here.  Of course, a number of WoC unit's do not have the option of taking Marks and are also lumped in here.  You will rarely see Chaos Undivided Warriors on the tabletop anymore.  Sorcerer's are the most likely to be unmarked, in order to give them access to the BRB lores.  The other unit that is most commonly unmarked is Chariots, since it saves points and it usually isn't that useful to give them a Mark.
Pros:  Access to BRB Lores, Cheap     Cons:  None, other than not having a Mark!
Common Units: Sorcerers, Chariots, Hellcannons, Trolls

Khorne:  Admittedly, my favorite Mark, both from a gaming perspective and the background of the game.  Is there anything better than having a horde of Khorne worshipers cut down your enemy and screaming 'Blood for the Blood God!, Skulls for the Skull Throne!'..is there anything more annoying either if done repeatedly?  Probably the second most popular of the Marks at this time.  The +1 Attack (Frenzy) combined with the ItP stacks up really well with most WoC units.  From the ever popular Khorne Marauder Horde with Great Weapons, to Khorne Chosen with AHWs (after a couple buffs, usually putting out 5 - St 5 attacks apiece!) or a nasty Khorne Lord build, if you want to bring the pain in CC this is the Mark for you.  Frenzy rules have changed enough that it isn't the liability it used to be.  You do need to be aware that you'll have to pursue/overrun after you smash your opponent and plan accordingly. The other problem is that a Mono-Khorne list isn't going to hold up in the Magic Phase very well.
Pros:  +1 Attack, ItP 
Cons: Most Expensive Mark, Lose Combat and you lose Frenzy, Forced to pursue/overrun. No Magic!
Common Units:  Marauder Horde w GWs; Warriors w AHW or Hal/Shield, Chaos Knights, Lords and Exalted characters.

Tzeentch:   This is probably the most popular Mark in 8th Edition.  The rule is subtle, simply a +1 to Cast and a +1 to existing Ward Saves/or a Ward Save of 6 for units that have none intrinsic.  Obviously a plus for Magic casters, since a Lvl 4 Tzeentch  Sorcerer Lord will be adding +5 to his casting rolls.  It also stacks nicely with any of the BRB Magic items that grant a Ward Save.  It's on close combat units that the rule is a bit more subtle.  Since the HW/Shield save is technically a Ward Save, the Mark of Tzeentch gives you a 5+ instead of the normal 6+ Ward Save.  This can make a unit of Tzeentch Warriors with HW/Shield pretty difficult to kill.  It also has seen the Tzeentch Marauders w HW/Shield Horde gain a lot of popularity.  Chosen of Tzeentch are also very popular in tournaments, since trying to kill a bunch of 3+ Ward Save Chosen can be nearly impossible.
Pros:  +1 Cast/Ward Save, Fairly cheap mark.  Cons: Tzeentch Lore is mediocre, Opponents hate you!
Common Units: Sorcerers, BSBs, Warriors w HW/Shield, Knights w Blasted Standard, Chosen, Warshrines.

Nurgle: Although there are some die-hard Nurgle Warriors out there, most of them are in it for the modeling and background, not for the competitive aspects of the Mark.  The Mark of Nurgle subtracts -1 from opponents shooting at you and -1 Weapon Skill when they attack you in CC.  The Mark doesn't affect Warmachines shooting at you, which are the main shooting attacks you need to worry about with WoC.  Although it's nice when Elves, Bloodletters and other Warriors need a 4 to hit you, it isn't really a game changer.  This Mark isn't really bad, it's just that Khorne and Tzeentch are better.
Pros:  Good against Shooty Armies (anyone still play these?) and high Weapon Skill armies.
Cons:  Expensive Mark, Nurgle Lore is mediocre, Painting Filth, Pus, Buboes, etc.
Common Units: Nurgle Knights with Banner of Rage, Festus in a Khorne Marauder Horde

Slannesh:  What used to be a very common Mark in 7th has all but disappeared in 8th Edition.  The Mark confers Immunity to Panic, Fear and Terror which isn't the boon it used to be.  Between Fear and Terror being basically nerfed, rerolling with BSBs, and the advantages the other Marks give you, poor Slannesh is definitely bringing up the rear.  The only time this Mark is still really useful, is when you put it on a small unit of Marauder Horse which makes them immune to Panic tests.  There is also an anti-leadership build that can work, when combined with Hellcannons, but it's risky and obviously doesn't work at all versus ItP armies.
Pros: Cheapest Mark, Immune to Panic, Fear and Terror
Cons:  No longer much benefit, Lore doesn't work against ItP units/armies.
Common Units:  Marauder Horse

So there you have it, the take on current Marks.  I barely touched the Magic Lores, since I intend to hit each Lore in a detailed breakdown later.