Pros for Orcs:
Tough, Strong motherfuckers.
Disciplined as fuck, sometimes.
Infamously, terrifyingly strong infantry.
Intimidating to face on the battlefield, make formations break easier.
Durable.
Fast.
Stubborn, usually fight to the death when even slightly cornered.
Cons for Orcs:
Very rag-tag. They may look more badass and battle-hardened for it, but their weapons and armor almost always look hashed-together, beat up, old, or any combination of those things. Their craftsmen, (if they have any that aren't just other peoples enslaved) can't seem to be arsed to make shiny new things for them.
They're all dumbfucks, and fall into obvious traps.
Usually aren't portrayed as having good archer support, or mages of any kind that are worth half a shit. They never have good cavalry, and if they do, their animals are either disobedient or it's reserved for warriors so elite that there's hardly enough for a unit and it doesn't make any noticable difference on the battlefield.
Scared of magic, scared of fire, scared of sunlight, scared of foolish superstitions.
They have very poor leadership on their own, and are bad at following directions. They fall into infighting and squabbling all too easily, constantly kill each other for shit reasons, might even start attacking friendlies on the battlefield for looking at them funny. They can only seem to live in tribes in other civilizations' abandoned caves and dungeons for this reason. Notice how the only people who can seem to get a proper army of orcs together are either the big bads, guys with super magical powers that terrify them, or "Special Orcs", which are orcs, but smarter than the average orc. Even then, they're often paired with Goblin hordes as elite troops, since Goblins are usually shown as more obedient creatures and Orcs seem to buy into mob mentality, I guess. Even then, you still get upset overlords yelling at their minions and demanding to know how they possibly could have lost a couple of Hobbits.
They love fighting. They love it far too much. They will meet anything and anyone on the field in open combat simply because it's fightable, and are likely to open up the castle gates during a siege just because they want to try and kill something.
Despite being stubborn and difficult to demoralize, there are also an astounding number of portrayals from D&D modules to old fantasy novellas that show orcs as being exceedingly cowardly and petty, and there might actually be an explanation for that. When they're in the zone, they'll break formation and leave everyone next to them open, because they want to charge into everybody else, which makes all the other orcs either charge because they don't know what the fuck's going on, or route with their tails between their legs because they think the line's broken and they can't defend it anymore. Either way, that's a good way to lose entire blocks of infantry at once, which is the Orcs' strongest (and only formidable, compared to other races) kind of unit. It's also a good way for them to be unable to hear what the fuck their commander is saying, which leads to the inevitable defeat, which leads to a very angry overlord, which leads to lots of orcs being thrown into a volcano or whatever overlord execution method is fashionable at the time.
And also, I know this isn't the deal with all orcs, and I know that a lot of other races have this too, but it seems especially prevalent in Orcs for some reason: BARE-TORSO ARMOR. FOR FUCK'S SAKE, WHAT THE FUCK IS WRONG WITH YOU!? YOUR HEART IS NOT IN YOUR SHOULDERS, IT'S IN YOUR CHEST! SPEND YOUR IRON ON A FUCKING CUIRASS FIRST, JESUS CHRIST!
Dwarf Cons:
Short.
Throwable.
Short.
Greedy.
Short.
Proud.
Short.
Dwarf Pros:
Actual strategic thoughts are in their heads. In fact, they're quite good at it.
Steampunk/magic technology, gunpowder weapons, flamethrowers, traps, etc.
Good at digging, can stealthily tunnel into strongholds and ambush from trenches.
Strong as fuck, not even for their own size, but usually for human-sized people too, in a lot of interpretations.
Well-crafted weapons, armor, etc. and lots of it.
Shiny stuff that hurts cave-dwelling Orc eyes.
Can hide easily for guerilla warfare.
Big shields and little bodies, virtually impossible for archers to deal with, if the orcs even have any.
Fierce and indomitable, difficult to demoralize a unit.
Crossbows. That's death,
Difficult for big guys to hit without bending over, making them easy to knock off balance whenever they do.
Capable of actually building their own empires and strongholds.
Strong, heroic leadership, usually with excellent strategies backing it up.
They're a civilised medieval society, so they likely have treatises and actual martial arts behind their weapons, making them incredibly difficult to deal with, even if the orc's bigger than they are, because an orc warrior's fighting style usually relies on the fact that the orc is bigger, whereas Dwarves have been fighting guys who are bigger than them in most of their wars and have trained their soldiers in precisely what methods to use when dealing with them, else the orcs or even the Dark Elves would own all their big fortresses and mines already, wouldn't they?
Actual, proper infrastructure. Not everybody's a warrior, but they have farms and medicine. Their soldiers are healthier, stronger, have more stamina, are, weather and parasite-resistant because of it, and less prone to keeling over and dying of dysentery or whatever other medieval fantasy disease of the day during long marches.
They have small bodies, and require far, far less supplies to fuel them for a day, making them especially resilient during sieges, long marches, or virtually any logistical situation, really. Especially since orcs don't even know the word "Logistics". Their armies are supplied by raids, which can cause unnecessary casualties to their armies, which doesn't always have a good/sustainable payoff given their tendency to burn/tear everything up, and they divvy supplies up not based on need, but on who found and ate it first, and looks like they could beat the shit out of you if you don't give them your loot. And Orcs are big, so they need to do this A LOT to sustain themselves and their appetites, and all that meat they eat (In a lot of universes, they're actually carnivorous) isn't really conducive to long-term energy, meaning they have to take starving breaks in between supply raids. Vicious cycle, orc warfare. Not to mention that, since orcs have to pillage everything, they're probably going to end up pissing off people who weren't really involved in the war to begin with and be confronted with even more fucking enemies then they had before.
All in all, Orcs would do what they do best: Die at the hands of the race that was designed with Player Characters and protagonists in mind. I daresay Dwarves would stand more than a reasonable chance of winning in 1v1 combat, the odds would be stacked against Orcs in most battle situations, and Dwarves would most certainly win any full-scale race war. There's several reasons why orcs can't even build their own proper civilizations.
