spec ops
is the best variation when it comes to closing distances and limiting your opponent's movement. the mixup game is great as well but i will not talk much about what makes spec ops a good variation because i am sure you already know which is why you are voting it for best variation i will talk about the disadvantage and advantages it has as a variation vs brawler and weaknesses in spec ops as well
stamina
as you know stamina is very important in this game but it is much more important if the character you are using is cassie cage. the needs for stamina in spec ops is even greater than the needs for it in brawler. so when it come to stamina brawer has an advantage because it needs it less than spec ops
damage and combos
brawler has the best damage out of all variations without the need to use meter. spec ups sacrifice a lot of damage in a match to try to set up her missile however only the ex missile after a combo put your opponents in a position in which they most guess what is coming next. this mean specs ops sacrifice damage and meter to be able to properly setup her opponents for a mixup after a combo. brawler does not sacrifice damage and does not need meter to do this however the mixup in spec ops at the end of a combo after using meter it is better. you can finish your combos with b124 to get more damage in spec ops but that is still less damage than brawler and put your opponent at full screen forcing you to use a bar of meter and a bar of stamina to get a mixup after ex missile. in my opinion brawler has a small advantage when it comes to setting up your opponent after a combo because it does not need meter and it does more damage and gets a hard knock down all at the same time.
corner game
there is not question here opec ops has the best corner game lol this variation is deadly in the corner. brawler does not get anything special in the corner so coner game is a big win for spec ops
poke and close game
no much to talk about really brawler close game is just better. 212 is very useful in brawler and has one of the best OS in the game between the throw and the flip kick
meter
specs ops needs to use meter for ex missiles to be more effective making it a meter heavy variation. you will have less meter to break combos and to ex flip kick brawler does not need to be using meter so the variation will always have meter to break and meter to flip kick however when spec ops use meter it is to make damage so it is kind of hard to tell which meter game is better i personally like both meter game for each variation
notes
using missiles whithout hitting your opponent first is risky because your opponent can run d2 you and take the hit of the missile and cassie can not to get up in time and combo. which mean she is loosing that trade because a d2 does like 14% while a regular missile does 5% so using regular missiles in footsies is no such a good idea if your opponent is on point with this.
their is options to do not have to deal with the mixup of the ex missiles right now people have yet to explore the option their characters have to deal with it but blocking is not the only thing you can do.
i think spec ops is good but right now it look better than it really is because it is early in the game and people have yet to learn their options against it. brawler is just going to get better with time