If you're sick and tired of getting owned by Liu Kang, then picking Jax is your best bet. At his finest, Jax will bash Kang around like a rag doll, and look like an impenetrable tank. Kang's speed and fireballs will force Jax to play more cautious than usual however.
KANG
Against most fighters, a barrage of high, low, and instant air fireballs is a good strategy. That's no different in this match. You can really confuse even the best Jaxs with this play. At the very least you're doing a bunch of chip damage. At the best, you're knocking Jax out of jump-ins or hitting him before he ground pounds/wave punches. Kang also does well to pressure Jax up close with sweeps, punches and jabs. Flying/bicycle kicks will really get you killed fast if blocked, so only sneak them in occasionally. A great Jax won't jump much, but when he does, anti-air with uppercut, aaHK or aaHP/bike kick. I'm very successful against many Jaxs by throwing a lot of fireballs, but then getting super aggressive. Jax does not like to be pressured, and if he throws a HK to try to keep you away, you can duck and bicycle kick him. Low toes are great at keeping Jax from ground pounding when you're within sweep distance.
JAX
Golden punches per usual, make Jax a brick wall. You'll eat lots of chip damage in this match doing that, but if you get good at them, you will basically be untouchable. Block all low fireballs and instantly do a ground pound. Throw wave punches from afar to keep Kang honest. Punish all flying attacks by blocking and JK/backbreaking. Crouch punch, crouch punch, ground pound is an excellent play when Kang tries to move in close. If Kang gets predictable with air fireballs, HK him out of the air. Jumping in this match is a toss-up. If you connect with Kang in the air you can combo it with a backbreaker. Also if he low fireballs as you JK him, you can get a ground pound in before Liu can recover. But jumping is also a dangerous play vs the speed and spam of Kang. You'll notice the best Jax players RARELY jump, especially in this match.
Could any Kangs touch XiongBros' Jax? He played before my time on PS3, but from what I've seen and heard, no.
Jax at his best is too much for Kang.
7-3 for Jax.