>PanO
Very direct. They like shooting people and are good at it, with lots of high tech toys to help them win firefights and a wide range of great heavy infantry and gundams. They lack some low tech tricks like smoke grenades and warbands though.
>Yu Jing
Generalists with an emphasis on excellent heavy infantry. They have a few smaller specialties like camo-busting and close combat, but they're mostly all-rounders.
>Ariadna
Low tech faggots. They get cheap troops, lots of camouflage and werewolves that rip and tear, but they also lack a lot of really good tech like visors that can see through smoke, superior TO camouflage, robots, conventional 2 wound heavy infantry, hacking (though they also can't be hacked for the most part) and high tech guns.
>Haqq
Lower tech, but nowhere near to the extent of Ariadna. They focus on various tricky tricks and cheap light irregular troops, and also have the best and most numerous doctors in the game. Good heavy infantry and TAG as well, but not much to choose from and they're not the best in a straight fight.
>Nomads
Board control is the order of the day. They have great defensive troops and the best hacking network around, as well as a bunch of fancy utility troops. High tech in some areas, but tend to be lacking when it comes to direct combat. They can fuck you around, but in a different way to Haqq.
>ALEPH
Elite army with extremely tough troops. Very high tech as well, but they pay for it. Unlike PanO, they still have smoke, and have some less direct toys as well like super hackers.
>Combined Army
Also an elite army, but different. Not so much focus on toughness and more on fancy gimmicks and unique tech. Very disciplined as well, losing your lieutenant is rarely a problem and CA almost never goes into retreat mode.
>Tohaa
Fucking weird. They get their own special fireteam, two wound troops everywhere, weirdo bio-hacking, an obsession with viral weapons, etc. Generally just strange and deeply disgusting.