NOTE: Below I describe each race and give a rough view of their special abilities. I tried to avoid any direct specifics about the mechanics behind a particular skill because these can be adjusted by the host, and are quite complex at times. The best source for detail about these races' abilities is the actual host program documentation, which can be found at Tim Wisseman's VGA Planets page.
The Federation's policies also make them a haven for scientists and engineers. They have some of the most advanced scientific and specialty starships. And, in battle, thier engineers can work wonders with their weapons and shield systems. Finally, their engineers have perfected a way to refit their ships without completely dissasembling them. This is a great advance over the alternate method of recycling of parts after complete destruction of the old ship.
The Gorn are a large reptilian race that is very aggressive. They specialize in ground combat, but also have several advantages in space combat. The Gorn ship crew is so dedicated and steadfast, due to a naturally high pain threshold, that a Gorn ship can sustain damage that would make any other ship explode. They also use cloaking ships. Making thier ability to drop super powerfull ground troops from a cloaked ship a nasty suprise for unsuspecting colonists.
As reptiles, they are extreamly efficient mineral miners(Don't ask me, it's Tim Wiseman's game). And, due to thier extream skill at ground attack, a hiss to the natives will prevent them from revolting in the face of high taxes.
The Romulans are known for stealth. They posses more cloaking ships than any other race. They are the only race whos largest battleship cloaks. Their largest ship is also the least expensive for the fire power.
The Romulans are also excelent spies. They can infiltrate a planet's government and trick them into handing over virtually anything. Occasionaly the planet's defence forces will detect the infultration and explode their arsonel to attempt to decloak the spy ships. Once found, the usually light spy ships are quite vulnerable.
The Klingons are a warrior race. They posses cloaking ships and are excelent ground troops. Prefering to be in up-close battles, their ships are usually not heavy in fighters or torpedos. Most of thier ships have more beam weapons than other ships in their class. This makes them excelent mine sweepers.
The Klingon ruthless efficiency allows them the ethical leaway to pillage planets and destroy native and colonist cities and take the plunder for profit. They also have special ships designated for suicide missions. They will kill themselves to detect and uncloak enimy ships, or as a nasty surprise. It's very difficult to stop a ship whos captain is intent on blowing himself to smitherines.
The Privateers are known for being theives. They survive on stealth and trickery. By hiding behind a cloaking device, they are able to steak out their prey and rob the subject's ship of cargo and fuel. Their ships are especially suited for this task because many of them use special "gravatonic" engines that can travel twice the distance in the same amount of time as all other ships with equivalent engines. These privateers are also ruthless killers. They specialise in killing the crews of the ships they battle to preserve the ship's hull for salvage. They can tune all beam weapons to tripple crew kill capacity. And, if a ship runs out of fuel, they are expert at forcing crews to surrender while under tow.
The Tholians are known for their use of the web mine. Web mine fields are very dence and you are almost sure to hit a mine if you traverse one. Once in the mine field, you will be drained of fuel. Then, much like the privateer race, the Tholian Crystal People will capture your fuel-drained ship.
The Cylons are known for making fighters and laying mine fields. They have an array of some of the toughest ships in the galaxy. And, they are so efficient at making mine fields, they get four times the mine field out of the same material as anyone else.