There are a few things you really need to know about Orcs. Firstly, something which ignored by many new gamers is their base size of 25mm. This is 25% bigger than most other race's rank and file bases and that can be a material difference.
Consider a unit of 20 orcs vs a unit of 20 of their arch rivals - Dwarfs. If both units deploy with a front rank of 5 models, to ensure they have their maximum rank bonus of 3, then the Dwarf unit will have a frontage of 100mm and the Orcs a frontage of 125mm. In a worst case scenario this could mean 5 dwarfs fightin 4 Orcs. Big deal you might think, well it could well be if your Orcs rout and then run through another unit causing panic.
In Warhammer Fantasy Battle the small details count.
There's another thing about Orcs, just like Goblins they will not be under your full control at all times due to animosity. Rock lobbers and spear chukka crew are not affected but say you had 12 other units then, on average, 2 of them will be squabbling amongst themselves and another 2 will be WAAAGHing (possibly against your wishes). See my post on animosity.
So that's the bad news and here's the good news...
Orcs are tough, as tough as Dwarfs (which is pretty tough if you've ever fought one !) They are also relatively cheap considering their fighting abilities so there's no excuse in fielding fighting units of 10.
Orcs also have choppas which proffer a +1 to strength in the first round of combat. So you need to try to get the first hit in (ie charge) to make the most of this (although you won't get that luxury against High Elves who always strike first anyway)
Deploy Orcs in numbers, lots of numbers. Also, give some of your key units 2 choppas for that +1 str.
Now Big Uns. These meaty mothers are ace ! They're like orcs but with +1 Ws and +1 Str sadly their initiative remains at 2 so once against these units need to charge into combat.
I said units above because you can have multiple units of Big Uns but only if you field the Orc Lord Gorbad Ironclaw, otherwise you can only upgrade one unit of Orc Boyz to Big Uns.
There's a problem with this though in a 2000 pts game, it means you cannot have Grimgor Ironhide !
If your enemy is likely to bring along a really tough beastie like a dragon then I'd take Grimgor otherwise Gorbad is a possibility, especially if you like my next 'did GW make a mistake' tip.
In the rules for Big Uns it says that a unit of Big Uns can use a standard of up to 50pts. It does NOT say one unit or a single unit. So, if you use Gorbad then updrage all most of your Orcs to Big Uns and give them all magic banners ! You can make your army virtually immune to non-Irresistable Force magic !!! Just take a few Mork Spirit Totem banners, that should cheese off all the enemy spell casters :) Also, for attackimg potency and to make sure you get the first charge try Gork's War Banner (+D6 to charge move). And don't forget to give some of your Big Uns Nogg's Banner of Butchery (one use only but +1 attack, use it on your charge for 3 strength 5 attacks with choppas per Big Un !
If I was playing a 3000 pt game I would take both Gorbad and Grimgor, even if the enemy was expecting me too. Yes, they're that good !
Nogg's Banner of Butchery
