In this overview I will be going through most of the units in the Ogre Kingdoms army, providing some of their advantages and disadvantages and other info that you may find useful.
Tyrants and Bruisers
Tyrants and Bruisers are the combat characters of the Ogre army list. Both are very difficult to kill, with high wounds and toughness. They have access to a good selection of mundane weapons, as well as the common and army specific magic items. Considering their size, they have only an average leadership, quite surprising for something twice as tall as any Empire soldier. They are powerful in close combat with strength and number of attacks but struggle to compete with other races on the weapon skill side of things. Tyrants are best leading your most powerful regiments, being either Maneaters or Ironguts most of the time. In my opinion Bruisers are better off helping the weaker units like Bulls keep up their combat resolution score.
Slaughtermasters and Butchers
These are the spell casters of the Ogre army. They have all six spells from the lore of Gut Magic, and these spells are great for enhancing the combat abilities of your Ogres as well as causing panic in the enemy and causing destruction to them in the form of magic missiles. Most of the spells can be quite destructive to the casters as well, so I would always recommend having a Halfling cookbook magic item on your favourite Butcher to ensure he survives his magic phases. They are also pretty good in combat, being Ogres, so the typical mage hunters can have more difficulty with them compared to other army mages when the Butchers give as good as they get in hand-to-hand.
The Hunter is a very useful character for flanking. His harpoon launcher acts as a weaker bolt thrower and if you put him on the flank of an enemy and fire, you may be able to cause some significant damage to help your Ogres in combat later on. This Ogre's ability in combat is also useful in taking on fast cavalry. Charge him in there, and he should rip a good few of them to pieces, and as fast cavalry are usually far away from the general, they should break easily. Then you just send your cats to run them down.
Bulls have access to a relatively good selection of weapons to choose from, personally I prfer Ironfists. You can choose to use it as either a shield or an additional hand weapon in close combat, which is handy for dealing with specific threats.
Ironguts are supposed to be the elite bodyguard of the Tyrants. However, they are exactly the same as Bulls, but with great weapons and heavy armour and a slightly better leadership. I would personally recommend Maneaters for the job instead. The Ironguts' great weapons do make them highly useful in combat though, the extra strength provided by these weapons is a great thing to have on any Ogre. Nobody should ever want to get into charge range of a unit of Ironguts for this reason.
Unbelievably the Gnoblar, though four times shorter than an Ogre, can be used as a screen against missiles. They are only two points, so taking a big unit to screen most of your army will be affordable. Also, if they panic for whatever reason and flee through your other units, the Ogres and other Gnoblars will not be affected! Should the Gnoblars be lucky enough to actually get through all that without running, they can throw their 'sharp stuff' and taunt enemies towards them in a baiting move. A problem worth considering however is that if the Gnoblars do act as a screen, they can slow down your entire Ogre advance via their natural slower movement rate and potential bickering.
Gnoblar Trappers are skirmisher scouts in the Ogre Kingdoms army. With this ability they can be used to slow the advance of the enemy and even help protect the flanks of the Ogre regiments.
The Scraplauncher is the Ogre Kingdoms chariot and artillery piece. To all intents and purposes it's a stone thrower on a chariot, but better IMO. Instead of using the small template, it uses the larger one! However, the hits are weaker and allow armour saves, but with Killing Blow the scrap shots can be fantastic against man-sized multi-wounded models and heavily armoured enemies. The fact that it is also a chariot means that it can also fares well in combat, with its powerful charge that can cause significant damage through impact hits as well as the Rhinox attacks. It is definitely worth spending points on, the Scraplauncher's flexibility as a shooting and combat unit make it an extremely useful machine on any battlefield.
Leadbelchers are the missile troops of the Ogres, carrying old cannons and things they have stolen from the corpses of their dead enemies, or traded for with the Chaos Dwarfs. Their cannons are short ranged, and quite likely to blow up in the face of their gunner and other members of their unit. The Leadbelcher can misfire, and one of these misfires can potentially kill 2 of the Ogres in the unit, not just the carrier of the weapon. Though they are temperamental, the Leadbelcher cannon is one of the most accurate weapons in the game (forgetting about auto-hit weapons for the moment), as you ignore many negative to-hit modifiers. The fact that the Leadbelcher cannon is a one-use weapon unless you don't move for a turn to reload, which is incredibly difficult to do with a weapon with only a 12” range (the enemy will be extremely close). The best thing to do is to stick 2 or 3 on each flank. When the enemy flankers get too close, move up and then open fire. The power of the weapon should bring some of them down, and force a panic test if you're lucky, and then for your next turn you will be within charge range, so you may be able to get the rest of them in close combat and cut them down.
In reality you will not get much opportunity to shoot with your Leadbelchers anyway, as by the time they enter 12” range the rest of your army will be pretty much in charging positions ready for combat, removing many potential targets.
Yhetees are another flexible unit in the Ogre Kingdoms army. They can move through terrain without penalty, making them an annoyance to Wood Elf armies especially and very handy on terrain heavy boards. They are also a must have against Undead with their ice weapons, as they count as magical they can harm any of those pesky ethereal units you would normally have to get a character to sort out or avoid for the whole game. Their high strength and plentiful attacks mean they should destroy those sorts of units with ease. Another useful thing about the Yhetee is that it is at -1 to hit in close combat, which means it can still remain alive even against the highest of weapon skill opponents, which is handy as the Ogres have very average weapon skill in general. Something that you must remember however is that they CANNOT see through terrain or finish a move in it, which means that if you're not careful as you leave the terrain you can find yourself to be in charge range of enemy troops and within shooting distance of enemy missile units. As you are likely to field Yhetees in units of three, one successful shooting phase can force you to take a panic test (on leadership 7 more than likely, if your general isn't nearby). For those reasons you will have to be careful about when and where you use the 'scale terrain' special rule.
Yhetees' high movement rate makes them as fast as many cavalry units in the game. This gives them another advantage in that they can outmanoeuvre slower enemy units and attempt to flank them. Use the scale terrain rule to move them close to a flank of an enemy unit, then smash them in the flank with the Yhetees while another Ogre unit hits them in the front - this is likely to do a lot of damage to the enemy unit.
Maneaters are the most powerful troops in the army IMO. They have access to mostly the same collection of weapons as the Tyrants and Bruisers, and are also in possession of heavy armour. This combination makes them lethal warriors, and a unit of them getting the charge in can be a real pain for your opponent. They have no access to a command group however, so combat resolution may be a problem with no standard, but the combination of their stubborness and throwing in a Battle Standard Bearer or your Tyrant can make up for this as well as providing more powerful attacks, making the whole unit a very tough nut to crack indeed!
Gorgers are one of the most useful things in the Ogre Kingdoms army. Being able to appear from any table edge you choose is a big help in defeating foes who would keep close to their own table edge. Gorgers are also able combatants and will prove their worth in the destruction of enemy artillery, which is an ability desperately needed to ensure the survival of your most likely heavily outnumbered Ogres.
They also have a number of fantastic special rules, which enhance their use immensely, and these things help them in their role as an annoyance greatly.
The special character Skragg the Slaughterer will make your Gorgers even more lethal. Fielding him greatly increases the number of Gorgers you can take in your army, and as they are a special choice in a Skragg army it also allows you to use your rare slots for other things such as Maneaters or Slave Giants. In addition, as Skragg gains kills your Gorgers become more and more deadly - true killing machines that will be difficult for your opponent to deal with.