There’s a reason they’re know as “The Nightmare Empire”, they can be an absolute nightmare to face at times. They just do a lot of things well. They can go with the glass cannon approach and hit like a ton of bricks. They can bring masses of infantry that can bolster themselves through respawn mechanics and wear you down through attrition. Several casters can shut down your army through debuff spells and feats. They have some of the most powerful casters in the game with some amazing feats. Their weaknesses would probably be low armor and a less than dominant ranged game. They won’t be going toe to toe with a Khadoran jack and trading blows(unless they are able to stack some of their crazy good debuffs) and they probably won’t beat you with a gun line. This doesn’t mean that they don’t have any good ranged options because they do, just that they probably won’t center an army around that strategy.
Some people feel that Cryx has a few too many abilities and their casters are broken. I agree that they have some very good ones but they are all beatable. They just might give their army a little more room for error than some other factions. I like to call them the “Tryx” faction because outside of Legion, I don’t think any other faction has more ways to ignore game rules.